Nano-engineered coatings for anode active materials, cathode active materials, and solid-state electrolytes and methods of making batteries containing nano-engineered coatings

ABSTRACT

The present disclosure relates to a nano-engineered coating for cathode active materials, anode active materials, and solid state electrolyte materials for reducing corrosion and enhancing cycle life of a battery, and processes for applying the disclosed coating. Also disclosed is a solid state battery including a solid electrolyte layer having a solid electrolyte particle coated by a protective coating with a thickness of 100 nm or less. The protective coating is obtained by atomic layer deposition (ALD) or molecular layer deposition (MLD). Further disclosed is a solid electrolyte layer for a solid state battery, including a porous scaffold coated by a first, solid electrolyte coating. The solid electrolyte coating has a thickness of 60 μm or less and a weight loading of at least 20 wt. % (or preferable at least 40 wt. % or at least 50 wt. %). Further disclosed is a cathode composite layer for a solid state battery.

CROSS REFERENCE TO RELATED APPLICATION(S)

This is a continuation-in-part application of U.S. application Ser. No.15/167,453, filed May 27, 2016, which is a continuation-in-partapplication of U.S. application Ser. No. 14/727,834, filed Jun. 1, 2015.This application also claims priority to U.S. Provisional ApplicationNo. 62/312,227, filed Mar. 23, 2016. The entire content of each of theabove-identified applications is incorporated herein by reference.

TECHNICAL FIELD

Embodiments of the present disclosure relate generally toelectrochemical cells. Particularly, embodiments of the presentdisclosure relate to batteries having nano-engineered coatings oncertain of their constituent materials. More particularly, embodimentsof the present disclosure relate to nano-engineered coatings for anodeactive materials, cathode active materials, and solid stateelectrolytes, and methods of manufacturing batteries containing thesecoatings.

BACKGROUND

Modern batteries suffer from various phenomena that may degradeperformance. Degradation may affect resistance, the amount ofcharge-storing ions, the number of ion-storage sites in electrodes, thenature of ion-storage sites in electrodes, the amount of electrolyte,and, ultimately, the battery's capacity, power, and voltage. Componentsof resistance may be gas formation pockets between layers (i.e.,delamination), lack of charge-storing ion salt in electrolyte, reducedamount of electrolyte components (i.e., dryout), electrode mechanicaldegradation, cathode solid-electrolyte-interphase (SEI) or surface phasetransformation, and anode SEI.

Liquid-electrolyte batteries may be made by forming electrodes byapplying a slurry of active material on a current collector, forming twoelectrodes of opposite polarity. The cell may be formed as a sandwich ofseparator and electrolyte disposed between the two electrodes ofopposite polarity. A cathode may be formed by coating an aluminumcurrent collector with an active material. An anode may be formed bycoating a copper current collector with an active material. Typically,the active material particles are not coated before the slurry isapplied to the current collectors to form the electrodes. Variations mayinclude mono-polar, bi-polar, and pseudo-bi-polar geometries.

Solid-state electrolyte batteries may be made by building up layers ofmaterials sequentially. For example, a current collector layer may bedeposited, followed by depositing a cathode layer, followed bydepositing a solid-state electrolyte layer, followed by depositing ananode layer, followed by depositing a second current collector layer,followed by encapsulation of the cell assembly. Again, the activematerials are not typically coated before depositing the various layers.Coating of active materials and solid state electrolyte is not suggestedor taught in the art. Rather, persons of ordinary skill strive to reduceinternal resistance and would understand that coating active materialsor solid-state electrolyte would tend to increase resistance and wouldhave been thought to be counterproductive.

As with liquid-electrolyte batteries, variations may include mono-polar,bi-polar, and pseudo-bi-polar geometries.

In either a liquid-electrolyte or solid-electrolyte configuration,various side-reactions may increase the resistance of the materials. Forexample, when the materials are exposed to air or oxygen, they mayoxidize, creating areas of higher resistance. These areas of higherresistance may migrate through the materials, increasing resistance andreducing capacity and cycle life of the battery.

In the positive electrode, diffusion polarization barriers may form as aresult of these oxidation reactions. Similarly, in the electrolyte,diffusion polarization barriers may form. In the negative electrode,solid-electrolyte-interphase (SEI) layers may form. For ease ofreference in this disclosure, “diffusion polarization barriers,”“concentration polarization layers,” and “solid-electrolyte interphaselayers,” are referred to as “solid-electrolyte interphase” or “SEI”layers.

SEI layers form due to electrochemical reaction of the electrodesurface, namely, oxidation at the cathode and reduction at the anode.The electrolyte participates in these side-reactions by providingvarious chemical species to facilitate these side reactions, mainly,hydrogen, carbon, and fluorine, among other chemical species. This mayresult in the evolution of oxygen, carbon dioxide, hydrogen fluoride,manganese, lithium-ion, lithium-hydroxide, lithium-dihydroxide, andlithium carboxylate, and other undesirable lithium species, among otherreaction products. Various electrochemistries may be affected by theseside-reaction, including lithium-ion, sodium-ion, magnesium-ion,lithium-sulfur, lithium-titanate, solid state lithium, and solid statebatteries comprising other electrochemistries. These side reactionsresult in thickening of the SEI layer over time, and during cycling.These side reactions may result in resistance growth, capacity fade,power fade, and voltage fade over cycle life.

Three mechanisms are known to be responsible for these oxidationreactions. First, various reactions occur in the liquid of theelectrolyte. A variety of salts and additives are typically used inelectrolyte formulation. Each is capable of decomposing and providingspecies that may contribute to SEI layer formation and growth. Forexample, the electrolyte may include lithium hexafluoride (LiPF₆).

In particular, the reduction of LiPF6, into a strong Lewis acid PF₅,fosters a ring-opening reaction with the ethylene carbonate solvent ofthe electrolyte (EC) and contaminates the anode active material surfacein the presence of the Li+ ions. It also initiates the formation ofinsoluble organic and inorganic lithium species on the surface of theelectrode (good SEI layer). A good SEI layer is a Li+ ion conductor butan insulator to electron flow. A robust SEI layer prevents furtherelectrolyte solvent reduction on the negative electrode. However, themetastable species ROCO₂Li within the SEI layer can decompose into morestable compounds —Li₂CO₃ and LiF at elevated temperature or in thepresence of catalytic compounds, e.g. Ni₂+ or Mn₂+ ions. These productsof side reactions are porous and expose the negative active materialsurface to more electrolyte decomposition reactions, which promote theformation of a variety of layers on the electrode surface. These layerslead to the loss/consumption of lithium ions at electrode/electrolyteinterface and are one of the major causes of irreversible capacity andpower fade.

Typical liquid electrolyte formulations contain ethylene carbonate (EC),diethyl carbonate (DEC), and dimethyl carbonate (DMC) solvents. EC ishighly reactive and easily undergoes a one electron reduction reactionat the anode surface. The EC molecule is preferably reacted (solvationreaction) because of its high dielectric constant and polarity comparedto other solvent molecules. The electrolyte decomposition is initiatedduring the intercalation of Li+ into the negative active materialsparticles. An electron is transferred from the electrode to theelectrolyte salt (LiPF6 typically) to initiate an autocatalytic processthat produces Lewis acid and lithium fluoride as shown in Equation 1.The Lewis acid PF₅ reacts further with impurities of water or alcohols(Eq. 2 and 3) in the electrolyte to produce HF and POF₃:

LiPF₆

LiF+PF₅  (1)

PF₅+H₂O

PF₅+⁻OH₂  (2)

PF₅+H₂O

2HF+POF₃  (3)

Various other components of the electrolyte may undergo similarprocesses by interacting with the active materials and produce morefluorinated compounds and CO₂. At high state of charge (high voltage) orwhen higher voltage materials are used in the manufacture of the batteryelectrodes, e.g., nickel-rich compounds, the decomposition reactions areeven more electrochemically favored.

Second, reactions may occur on the surface of the active material. Thesurface of the active material may be nickel-rich or enriched with othertransition metals and nickel may provide catalytic activity that mayinitiate, encourage, foster, or promote various side reactions. Sidereactions at the surface of the active material may include oxidation atthe cathode, reduction at the anode, and phase transformation reactionsthat initiate at the surface and proceed through the bulk of the activematerial. For example, the cathode active material may includenickel-manganese-cobalt-oxide (NMC). NMC may undergo a phase transitionat the surface to form nickel-oxide or a spinel form oflithium-manganese-oxide. This may result in the evolution of CO₂, MN₂ ⁺,HF, and various oxidized species. These may form an SEI on the anodesurface.

In addition, less space is available in the remaining modified crystalstructures on the cathode surface of the active material to accommodatelithium ions in the crystal lattice. This reduces capacity. These phasesmay also have lower intercalation voltage than the original structure,leading to voltage fade. The more these secondary phases occur, thegreater the reduction in capacity for storing lithium ions and voltagefade. These changes are irreversible. Thus, capacity lost to these sidereactions cannot be recovered on cycling the battery.

Third, bulk transition of NMC to spinel also reduces capacity andvoltage. These reactions may initiate at the surface and proceed throughthe bulk material. These spinel transition reactions do not rely onelectrolyte decomposition or oxidation-reduction reactions. Rather,spinel is a more stable crystalline form having a lower energy state andits formation is thermodynamically favored.

These SEI reactions can increase resistance due to increased thicknessof a passivation layer on the active materials and/or electrodes thataccumulates and grows thicker over time. Concentration gradients mayform in the SEI. Electrolyte may become depleted in certain ionicspecies. Other elements, including, manganese, may be degraded at theanode side of the reaction, slowing lithium diffusion and increasingionic transfer resistance.

Some past efforts have applied material layers to the anode or cathodeof a battery by atomic layered deposition (ALD) to improve electricalconductivity of the active materials. See, for example, Amine, et al.,U.S. Pat. No. 9,005,816 for “Coating of Porous Carbon for Use in LithiumAir Batteries,” which is incorporated herein by reference in itsentirety. Amine deposits carbon to enhance conductivity.

One shortcoming of this approach is that the chemical pathways at thecathode and/or anode surface of the above side reactions remainunaltered. Amine's coating is not engineered. Rather, whatever materialis thermodynamically-favored is formed. The active materials are ceramicoxides that are not highly-electrically conductive. Amine depositscarbon, not to block side reactions but, rather, to promote electricalconductivity. Depositing a conductive material may enhance the chargerate but may not block these side reactions. Particularly in view of thefact that Amine's coating is electrically conductive and porous, theabove side reaction mechanisms may continue to operate.

In addition to the problems associated with prior art discussed above,the present disclosure aims to solve one or more of the followingproblems: SEI layer growth and degradation due to secondaryside-reactions at the electrode/electrolyte interphase; contactresistance due to increased thickness over time of the passivation layeron active materials or electrodes; phase transformations due tofavorable surface energy landscape; reduced rate capability due tohigher lithium diffusion barriers; cathode/anode dissolution processes;undesirable ionic shuttling reactions causing self-discharge.

For example, in the case of Lithium-ion batteries, the problems that canbe addressed by the present disclosure include: surface formation ofbinary metal oxide structures, which propagate inward, causing capacity,voltage fade and resistance growth. The problems that can be addressedby the present disclosure include: electrolyte oxidation at high voltage(e.g., top of charge), which depletes electrolyte (and consequently Liions), and produces HF causing transition metal dissolution. Transitionmetal dissolution alters the structure of the cathode surface, therebyincreasing Li transport resistance. Both transition metal ions andelectrolyte oxidation products shuttle to the anode and causeself-discharge and excessive SEI formation, further depleting theelectrolyte. Transition metal deposition also increases the Li transportresistance of the SEI. Electrolyte oxidation also creates gas whichdelaminates the electrodes. The problems that can be addressed by thepresent disclosure also include: Ni segregation to surface, resulting inseveral processes that cause voltage, capacity, and power fade,including: higher Li diffusion barrier (poor rate capability andcycleability), reaction of electrolyte with NO⁺ at high voltage that hasvarious issues of electrolyte oxidation as well as deterioration of thecathode/electrolyte interface, and decreased Ni—Mn interaction causingMn³⁺ reduction (which may lead to spinel formation). The problems thatcan be addressed by the present disclosure also include: spinel phaseand rock salt phase nucleation and propagation from the surface (voltagefade). The spinel phase also generally has lower capacity than layeredstructure (capacity fade).

Various approaches have been developed for addressing theabove-mentioned degradation mechanisms that cause capacity, voltage, andpower fade. However, these approaches do not directly address thefundamental mechanisms and therefore can only at best be partiallyeffective. These approaches include using new cathode materials ordopants, new syntheses (e.g., hydrothermally assisted), chemicalactivation, pre-lithiation, optimization of particle size distribution,cathode structuring (e.g., uniform metal cation distributions,core-shell or gradient metal distributions, and optimization of primaryand secondary particles), and electrolyte optimization. It is notuncommon to see improvements in cycle lifetime of high energy batteriesthrough the above approaches. However, the fundamental degradationmechanisms, such as cathode structure transitions from layered to spinelcrystal structures, have not been shown to be fully avoided. Forexample, electrolyte additives, especially synergistic additivecombinations including vinylene carbonate (VC), have been shown todecrease the rate of electrolyte oxidation and capacity fade. However,these processes still occur, and the maximum factor of improvement isoften shown to be less than 50%.

The common shortcoming of all the traditional approaches is that they donot alter the chemical pathways present at the cathode and anodesurfaces, the sites where all degradation mechanisms initiate. Forexample, changes to the electrolyte composition and cathode compositioncan change the rates of the processes that occur at the surface, butthey do not remove the sites of contact between the electrolyte and thecathode. There is a need for a new battery design that blocksundesirable chemical pathways.

All-solid-state secondary batteries employing inorganic solid stateelectrolytes (SSEs) offer a significant safety advantage overconventional liquid electrolyte-containing batteries, making them highlydesirable for next generation energy storage. The safety feature ofall-solid-state secondary batteries lies in the SSE which functionselectrochemically and structurally within the battery, which reduces oreliminates the need for flammable liquid electrolytes. Much effort hasgone into developing new SSEs with suitable electrochemicalcharacteristics such as high ionic conductivity, chemical stability athigh voltage, as well as into its structural role as the separatorbetween the cathode and anode. However, prior to this invention,all-solid-state secondary batteries have not been commercially viabledue not just to performance drawbacks such as the low conductivity ofSSE materials relative to liquid electrolytes and the lack of chemicalstability with conventional electrode materials, but also the inabilityto handle these materials in conventional secondary battery processingsystems and to manufacture solid state batteries outside of a controlledenvironment devoid of moisture and oxygen.

SUMMARY

The present disclosure offers a new battery design that blocksundesirable chemical pathways. The anode and cathode coatings candirectly address the degradation mechanisms. Some examples of thecoatings include surface metal cation doping, metal oxide or carbonsol-gel coating, sputter coating, and metal oxide atomic layerdeposition (ALD) coating. Of these, ALD coating offers impressiveresults due to its thinness (incremental atomic layers), completeness(leaving no uncoated surfaces), and that it does not remove electricallyactive material. In contrast, surface doping of cations replacing Mncations reduces capacity by removing Mn intercalation centers. Sol-gelcoatings give non-uniform thickness and extent of coating, where thethicker areas have high resistance and the non-coated areas experiencedegradation. However, ALD-coated anodes and/or cathodes commonly show nocapacity, voltage, or power fade in batteries. Because proper ALDcoating on particles leaves no uncoated surfaces, it can completelyblock electrolyte oxidation, cathode cation dissolution, and SEIprecursor shuttling. Moreover, because binary metal oxide and spinelphase nucleation and growth initiates from the surface, completecoverage of cathode surfaces by ALD coating removes all nucleation sitesand therefore prevents cathode restructuring. Unfortunately, ALD coatingis known to introduce other well-known limitations such as lower ratecapability and power, limited scalability, and high cost. Moreover, themajority of coating work has focused on NMC, and the rigid metal oxidecoatings applied by ALD are quickly broken and rendered ineffective forSi anodes. The present disclosure introduces novel variants of ALDcoating that offer characteristic advantages of ALD coatings but mayovercome one or more of the above limitations. With the disclosedtechnology, high energy, long lifetime cells with the improvements ofsurface coatings can be implemented in high-volume and electric vehicle(EV) applications.

Although the present disclosure is not limited to the below theory, thepresent inventors believe that altering the interface to reduce chargetransfer resistance, electronic resistance, ionic transfer resistance,and concentration polarization resistance may reduce the above-notedcomponents that would otherwise increase resistance. The presentinventors believe that it is desirable to inhibit undesirable chemicalpathways and mitigate side reactions. By altering the behavior of theactive material surface and tailoring and adapting its composition toreduce contact transfer or concentration polarization resistance, cyclelife of high energy density materials may be improved and power fade andresistance growth reduced.

Embodiments of the present invention deposit a coating on anode activematerials, cathode active materials, or solid state electrolyte. Thiscoating is preferably thin, continuous, conformal, and mechanicallystable during repeated cycling of the battery. The coating may beelectrically conductive or non-conductive.

In various embodiments, a cathode, anode, or solid state electrolytematerial is coated with a nano-engineered coating, preferably by one ormore of: atomic layer deposition; molecular layer deposition; chemicalvapor deposition; physical vapor deposition; vacuum deposition; electronbeam deposition; laser deposition; plasma deposition; radio frequencysputtering; sol-gel, microemulsion, successive ionic layer deposition,aqueous deposition; mechanofusion; solid-state diffusion, or doping. Thenano-engineered coating material may be deposited on the activematerials of the cathode, active materials of the anode, or the solidstate electrolyte prior to fabrication of the battery or after formationsteps are applied to the finished battery. The nano-engineered coatingmaterial may be a stable and ionically-conductive material selected froma group including any one or more of the following: (i) metal oxide;(ii) metal halide; (iii) metal oxyhalide; (iv) metal phosphate; (v)metal sulfate; (vi) non-metal oxide, (vii) olivines, (viii) NaSICONstructures, (ix) perovskite structures, (x) spinel structures, (xi)polymetallic ionic structures, (xii) metal organic structures orcomplexes, (xiii) polymetallic organic structures or complexes, (xiv)structures with periodic properties, (xv) functional groups that arerandomly distributed, (xvi) functional groups that are periodicallydistributed, (xvii) block copolymers; (xviii) functional groups thathave checkered microstructure, (xix) functionally graded materials; (xx)2D periodic microstructures, (xxi) 3D periodic microstructures, metalnitride, metal oxynitride, metal carbide, metal oxycarbide, andnon-metallic organic structures or complexes. Suitable metals may beselected from, but not limited to, the following: alkali metals,transition metals, lanthanum, boron, silicon, carbon, tin, germanium,gallium, aluminum, and indium. Suitable coatings may contain one or moreof the above materials.

Embodiments of the present disclosure include methods of depositing anano-engineered coating on cathode active materials, anode activematerials, or solid state electrolyte using one or more of thesetechniques. In an embodiment, a coating is deposited on cathode materialparticles before they are mixed into a slurry to form active materialthat is applied to the current collector to form an electrode. Thecoating is preferably mechanically-stable, thin, conformal, continuous,non-porous, and ionically conductive. A battery may be made using acathode active material coated in this manner, an anode, and a liquidelectrolyte.

In certain embodiments, a battery includes: an anode; a cathode; andeither a liquid or solid-state electrolyte configured to provide ionictransfer between the anode and the cathode; with a microscopic and/ornanoscale coating deposited either on the solid-state electrolyte, or onthe anode or cathode active material regardless whether a solid-state orliquid electrolyte is used.

Certain embodiments of the present disclosure teach nano-engineeredcoatings for use in a battery to inhibit undesirable side-reactions. Forexample, by coating an atomic or molecular coating layer on the activematerials and/or solid-state electrolyte, electron transfer from theactive materials to a passivation layer normally formed onto theelectrodes surfaces and into the electrodes pores can be prevented. As aresult, undesired side-reactions can be prevented. In addition, theatomic or molecular coating layer can limit or eliminate resistancegrowth, capacity fade, and degradation over time that cells experienceduring cycling. Furthermore, embodiments of the present disclosure mayinhibit undesirable structural changes resulting from side reactions ofthe electrolyte or solid state reactions of the active materials, e.g.,phase transitions. Batteries of embodiments of the present disclosuremay yield increased capacity and increased cycle life.

Certain embodiments of the present disclosure provide nano-engineeredcoating techniques that are less expensive alternatives to existingdesigns. These techniques may be relatively faster and require lessstringent manufacturing environments, e.g., coatings can be applied in avacuum or outside of a vacuum and at varying temperatures.

Another advantage of certain embodiments of the present disclosure isreduced cell resistance and increased cycle life. Certain embodiments ofthe present disclosure yield higher capacity and greater materialselection flexibility. Certain embodiments of the present disclosureoffer increased uniformity and controllability in coating application.

Other advantages of the present disclosure include: by using the ALDcoating disclosed in the present disclosure, the capacity and cycle lifeof a battery can be increased. The battery can be made safer by thecoatings disclosed. The ALD coating also enables high capacity, highvoltage, and materials with large volume change issues, and previouslyunusable materials. The ALD coating also increases surface conductivityand makes the SEI layer more functional as the ALD coating is engineeredin a certain way as opposed to be processed in a random process.

In addition, disclosed here are two methods for producing sufficientlystabilized SSE-based materials suitable for use in conventionalliquid-based electrolyte energy storage production facilities.

The first method is a vapor deposition process for an encapsulationcoating that is applied to a powder comprising SSE particles, whichprovides a suitable permanent, semi-permanent, sacrificial or temporarybarrier against oxygen ingress, or other permanent or semi-permanentinterfacial benefit to adjacent coated or uncoated particles in thefinished layer or system. Said encapsulated SSE particles can then becast, printed or coated as films (e.g. via a slurry or otherconventional approach, or a more advanced approach such as via 3-Dprinting) onto finished electrodes in conventional fabricationequipment, and the functionality of any semi-permanent or temporarybarrier is further designed (e.g., in composition, thickness, or otherphysicochemical attribute) to be sufficient enough to preventdegradation over the particular time scales the materials and films,layers or coatings thereof are exposed to a particular environment thatis substantially different than the substrate. Devices that comprise theinitially encapsulated materials produced in a non-inert environmentretain substantially similar performance to comparable devices producedusing current solid state techniques in an inert environment.

The second method is a vapor deposition process that produces the SSEmaterial itself using a conventional flexible porous separator sheet orweb as a template, which creates a flexible SSE comprising system thatcan be integrated using conventional device fabrication processes forintegrating a pristine separator. Atomic Layer Deposition (ALD)chemistries and steps or sequences of the appropriate solid electrolytecomposition can be deposited onto fixed or moving microporous substratessuch as separators, membranes, foams, gels (e.g., aerogels or xerogels,etc.) that are rigid, semi-rigid or flexible. For example, a known SSEcomposition such as xLi₂S(1−x)P₂S₅, where x is a molar ratio and rangesfrom about 10 to about 90 can be produced using a lithium source (e.g.alkyllithiums, lithium hexamethyldisilazide or lithium t-butoxide), asulfur source (e.g., H₂S) and a phosphorous source (e.g. H₃P) with otherbeneficial adhesion aids, promoters or steps (e.g., plasma exposure).Similarly, solid electrolyte layer comprising Li_(x)Ge_(y)P_(z)S₄, wherex, y, z are mole concentrations and range from 2.3<x<4, 0<y<1, and 0<z<1can also be produced easily using the right sequence of exposures of theaforementioned precursors along with the exposure of a germanium source(e.g., germanium ethoxide) interleaved. LLTO and LiPON can similarly beapplied using ALD techniques onto such substrates. In addition,Molecular Layer Deposition (MLD) techniques that produce hybridinorganic/organic coatings onto substrates with the same precision asALD can also be deployed for advanced SSE-incorporated separators. Ahybrid polymeric/LiPON coating can be applied using bifunctional organicchain molecules such as ethylenediamine, ethanolamine or similar as anitrogen source, to produce flexible and/or compressible MLD coatingswith high ionic conductivity on deformable/flexible substrates such asseparators suitable for use in batteries, fuel cells, or electrolyzers,or membranes used for a variety of chemical processes involvingreactions or separations. Similarly, lithium-containing polymers or ALDcoatings can also demonstrate higher ionic conductivity than coatingsdevoid of lithium. The advantage of one embodiment of the invention isthe subsequent encapsulation process that is applied to the producedflexible SSE-incorporated separator, which applies a similarencapsulating coating onto the exposed SSE surfaces throughout thesystem. Similar to the first method, devices that comprise the initiallyencapsulated SSE-incorporated separator produced in a non-inertenvironment retain substantially similar performance to comparabledevices produced using current solid state techniques in an inertenvironment. Currently, particles, slurries and separators can beconsidered part of a family of “drop-in ready” raw materials for batterymanufacturing operations, which can be surface modified while retaininga drop-in readiness aspect.

Varying compositions of the SSE-incorporated separator can be deployed,and particular compositions or loadings (relative to the separatortemplate) may be used for all solid state energy storage devices, andothers may be suitable for hybrid liquid-solid electrolyte based energystorage devices (e.g., through the incorporation of a conventionalliquid electrolyte such as LiPF₆ or one or more ionic liquids such asdescribed in WO 2015/030407 and U.S. application Ser. No. 14/421,055,which are incorporated by reference in their entirety). In someinstances of each case, a different encapsulation coating compositionmay be applied to SSE materials on the cathode-facing and anode-facinginterfaces, or further gradiated throughout a given coating layer, tofurther promote system compatibility. In the method in which SSEparticles are coated, a first layer comprising a cathode-stable SSEencapsulation coating (e.g. Al₂O₃ or TiO₂, LiAlO_(x) or LiTiO_(x),LiAlPO₄ or LiTiPO₄, LiAl_(x)Ti_(y)PO₄ or LATP, LiPON) may be cast onto afabricated cathode to make a first SSE layer, and a second layercomprising an anode-stable SSE encapsulation coating (e.g. LiPON oradvantageous MLD coatings) may be interposed between said first SSElayer and a fabricated anode. In the separator-based method, acathode-stable encapsulation coating can be applied to the side of theSSE-incorporated separator intended to be cathode-facing using one vapordeposition process, and an anode-stable encapsulation coating can beapplied (simultaneously or sequentially) to the side of theSSE-incorporated separator intended to be anode-facing.

One aspect of many embodiments of the invention relates to a populationof solid-state electrolyte (SSE) particles each coated by a protectivecoating, wherein the protective coating has a thickness of 100 nm orless and is obtained by atomic layer deposition (ALD) or molecular layerdeposition (MLD).

In some embodiments, the SSE particles comprise a lithium-conductingsulfide-based, phosphide-based or phosphate-based compound, anionically-conductive polymers, a lithium or sodium super-ionicconductor, and/or an ionically-conductive oxide or oxyfluoride, and or aGarnet, and or LiPON, and or Li-NaSICon, and or Perovskites, and orNASICON structure electrolytes (such as LATP), Na Beta alumina, LLZO. Insome embodiments, the SSE particles comprise lithium conductingsulfide-based, phosphide-based or phosphate-based systems such asLi₂S—P₂S₅, Li₂S—GeS₂—P₂S₅, Li₃P, LATP (lithium aluminum titaniumphosphate) and LiPON, with and without dopants such as Sn, Ta, Zr, La,Ge, Ba, Bi, Nb, etc., ionically-conductive polymers such as those basedupon polyethylene oxide or thiolated materials, LiSICON and NaSICON typematerials, and ionically-conductive oxides and oxyfluorides such aslithium lanthanum titanate, tantalate or zirconate, lithiated andnon-lithiated bismuth or niobium oxide and oxyfluoride, etc., lithiatedand non-lithiated barium titanate and other commonly known materialswith high dielectric strength, and combinations and derivations thereof.In some embodiments, the SSE particles comprise lithium phosphorussulfide or lithium tin phosphorus sulfide.

SSEs may be made using different methods, such as ball milling, sol-gel,plasma spray, etc.

In some embodiments, the SSE particles comprise a material having anionic conductivity of at least about 10⁻⁵ S cm⁻¹, or at least about 10⁻⁴cm⁻¹, or at least about 10⁻³ S cm⁻¹, or at least about 10⁻² S cm⁻¹, orabout 10⁻⁵ S cm⁻¹ to about 10⁻¹ cm⁻¹, or about 10⁻⁴ S cm⁻¹ to about 10⁻²cm⁻¹.

In some embodiments, the SSE particles have an average or mean diameterof about 60 μm or less, or about 1 nm to about 30 μm, or about 2 nm toabout 20 μm, or about 5 nm to about 10 μm, or about 10 nm to about 1 μm,or about 10-500 nm, or about 10-100 nm.

In some embodiments, the protective coating has a thickness of about 100nm or less, or about 0.1-50 nm, or about 0.2-25 nm, or about 0.5-20 nm,or about 1-10 nm.

In some embodiments, the SSE particles comprise a surface area of about0.01 m²/g to about 200 m²/g, or about 0.01 m²/g to about 1 m²/g, orabout 1 m²/g to about 10 m²/g, or about 10 m²/g to about 100 m²/g, orabout 100 m²/g to about 200 m²/g.

In some embodiments, the SSE particles are synthesized using a spraypyrolysis process, such as plasma spray or flame spray with a reducingflame.

In some embodiments, the protective coating comprises metal oxide, metalnitride, metal oxynitride, metal carbide, metal oxycarbide, metalcarbonitride, metal phosphate, metal sulfide, metal fluoride, metaloxyfluoride, metal oxyhalide, non-metal oxide, a non-metal nitride, anon-metal carbonitride, non-metal fluoride, non-metallic organicstructures or complexes, or non-metal oxyfluoride. In some embodiments,the protective coating comprises alumina or titania.

In some embodiments, the protective coating comprises a material havingan ionic conductivity of about 10⁻⁵ S cm⁻¹ or lower, or about 10⁻⁶ cm⁻¹or lower, or about 10⁻⁷ S cm⁻¹ or lower, or about 10⁻⁸ S cm⁻¹ or lower.

In some embodiments, the SSE particles are capable of retaining at leastabout 80 wt. %, or at least about 90 wt. %, or at least about 95 wt. %,or at least about 98 wt. %, or at least about 99 wt. % of theencapsulated electrolyte material after being exposed to ambient air for1 minute. In some embodiments, the SSE particles are capable ofretaining at least about 80 wt. %, or at least about 90 wt. %, or atleast about 95 wt. %, or at least about 98 wt. %, or at least about 99wt. % of the encapsulated electrolyte material after being exposed toambient air for 2 minutes. In some embodiments, the SSE particles arecapable of retaining at least about 80 wt. %, or at least about 90 wt.%, or at least about 95 wt. %, or at least about 98 wt. %, or at leastabout 99 wt. % of the encapsulated electrolyte material after beingexposed to ambient air for 5 minutes. In some embodiments, the SSEparticles are capable of retaining at least about 80 wt. %, of at leastabout 90 wt. %, or at least about 95 wt. %, or at least about 98 wt. %,or at least about 99 wt. % of the encapsulated electrolyte materialafter being exposed to ambient air for 10 minutes. In some embodiments,the SSE particles are capable of retaining at least about 80 wt. %, ofat least about 90 wt. %, or at least about 95 wt. %, or at least about98 wt. %, or at least about 99 wt. % of the encapsulated electrolytematerial after being exposed to ambient air for 30 minutes. In someembodiments, the SSE particles are capable of retaining at least about80 wt. %, of at least about 90 wt. %, or at least about 95 wt. %, or atleast about 98 wt. %, or at least about 99 wt. % of the encapsulatedelectrolyte material after being exposed to ambient air for 60 minutes.

In some embodiments, the coated or encapsulated SSE particles can beused for pressed or cast batteries of any size or shape or form factor.

Another aspect of many embodiments of the invention relates to a solidstate battery comprising a solid electrolyte layer which comprises theSSE particles described herein.

In some embodiments, the solid state battery further comprises a cathodecomposite layer in contact with the solid electrolyte layer (shared orindependent).

In some embodiments, the cathode composite layer comprises a cathodeactive material mixed with a conductive additive and an SSE (conductiveadditive might be ALD coated too).

In some embodiments, the cathode active material comprises a lithiummetal oxide, a lithium metal phosphate, sulfur, a sulfide such aslithium sulfide, metal sulfide or lithium metal sulfide, a fluoride suchas metal fluoride (e.g., iron fluoride), metal oxyfluoride, lithiummetal fluoride or lithium metal oxyfluoride, or a sodium variant of theaforementioned compounds.

In some embodiments, the cathode active material comprises a cathodeparticle coated by a protective coating having a thickness of about 100nm or less, or about 0.1-50 nm, or about 0.2-25 nm, or about 0.5-20 nm,or about 1-10 nm.

In some embodiments, the protective coating of the cathode activematerial in the cathode composite layer and the protective coating ofthe SSE particle in the solid electrolyte layer comprise the samematerial.

In some embodiments, the conductive additive in the cathode compositelayer comprises a conductive carbon-based material such as carbon black,carbon nanotube, graphene, acetylene black, and graphite, and any coatedversion of them.

In some embodiments, the conductive additive comprises a particle coatedby a protective coating having a thickness of about 100 nm or less, orabout 0.1-50 nm, or about 0.2-25 nm, or about 0.5-20 nm, or about 1-10nm.

In some embodiments, the protective coating of the conductive additivein the cathode composite layer and the protective coating of the SSEparticle in the solid electrolyte layer comprise the same material.

In some embodiments, the solid state battery is free of an anode layeror an anode composite layer.

In some embodiments, the solid state battery further comprises a lithiummetal anode layer in contact with the solid electrolyte layer.

In some embodiments, the solid state battery further comprises an anodecomposite layer in contact with the solid electrolyte layer.

In some embodiments, the anode composite layer comprises an anode activematerial mixed with a conductive additive and an SSE.

In some embodiments, the anode active material comprises carbon-basedmaterial (e.g., graphite, etc.), silicon, tin, aluminum, germanium,lithium variations of all (e.g., prelithiated silicon, etc.), metalalloys, oxides (e.g., LTO MoO₃, SiO, etc.), and mixtures andcombinations of each.

In some embodiments, the anode active material comprises an anodeparticle coated by a protective coating having a thickness of about 100nm or less, or about 0.1-50 nm, or about 0.2-25 nm, or about 0.5-20 nm,or about 1-10 nm.

In some embodiments, the protective coating of the anode particle in theanode composite layer and the protective coating of the SSE particle inthe solid electrolyte layer comprise the same material.

In some embodiments, the conductive additive in the anode compositelayer comprises a conductive carbon-based material such as carbon black,carbon nanotube, graphene, graphite, and carbon aerogels.

In some embodiments, the conductive additive comprises a particle coatedby a protective coating having a thickness of about 100 nm or less, orabout 0.1-50 nm, or about 0.2-25 nm, or about 0.5-20 nm, or about 1-10nm.

In some embodiments, the protective coating of the conductive additivein the anode composite layer and the protective coating of the SSEparticle in the solid electrolyte layer comprise the same material.

In some embodiments, the cathode composite layer and the solidelectrolyte layer account for at least about 40 wt. %, or at least about50 wt. %, or at least about 60 wt. %, or at least about 70 wt. %, or atleast about 75 wt. %, or at least about 80 wt. %, or at least about 85wt. %, or at least about 90 wt. %, or at least about 95 wt. %, of thesolid state battery, based on the total weight of the cathode currentcollector, the cathode composite layer, the solid electrolyte layer, theseparator layer if any, the anode layer or anode composite layer if any,and the anode current collector. In some embodiments, the separatorlayer and the anode layer or anode composite layer account for about 15wt. % or lower, or about 10 wt. % or lower, or about 5 wt. % or lower,or about 3 wt. % or lower, or about 2 wt. % or lower, or about 1 wt. %or lower, of the solid state battery, based on the total weight of thecathode current collector, the cathode composite layer, the solidelectrolyte layer, the separator layer if any, the anode layer or anodecomposite layer if any, and the anode current collector.

In some embodiments, the solid state battery has a first cycle dischargecapacity that is at least about 20% higher, or least about 50% higher,or at least about 100% higher, or at least about 200% higher, or atleast about 500% higher than a corresponding solid state battery inwhich the SSE particle in the solid electrolyte layer is not coated by aprotective coating, where both the solid state battery of the inventionand the corresponding solid state battery are fabricated under the sameenvironment (e.g., a non-inert environment comprising an ambient O₂content). In some embodiments, the solid state battery allows continuedcycling at about 20%-500%, or about 20%-50%, or about 50%-100%, or about100%-200%, or about 200%-500%, of the theoretical capacity of thematerial. In some embodiments, the protective coating of the SSEprevents growth of “native oxide” in ambient air to greater than about 5nm in thickness. In some embodiments, the protective coating of the SSEmaintains an oxygen content of no more than about 5% after exposure toambient air for about 24 hours. In some embodiments, the solidelectrolyte particle coated with the protective coating is adapted tomaintain an ionic conductivity of at least 10⁻⁶ s cm⁻¹, or at least 10⁻⁵S cm⁻¹, or at least 10⁻⁴ S cm⁻¹, after 1 hour of exposure to ambientair.

In some embodiments, the solid state battery is a lithium-ion battery.In some embodiments, the solid state battery is a sodium-ion battery. Insome embodiments, the solid state battery is a lithium battery.

Another aspect of many embodiments of the invention relates to a solidelectrolyte layer comprising a porous scaffold that is coated by an SSEcoating, wherein the SSE coating has a thickness of 60 μm or less.

In some embodiments, the porous scaffold is a porous separator. In someembodiments, the porous separator has a size of at least about 1 cm², orat least about 10 cm², or at least about 100 cm², or at least about 1000cm².

In some embodiments, the SSE coating comprises a lithium-conductingsulfide-based, phosphide-based or phosphate-based compound, anionically-conductive polymers, a lithium or sodium super-ionicconductor, or an ionically-conductive oxide and oxyfluoride. In someembodiments, the SSE coating comprises lithium conducting sulfide-based,phosphide-based or phosphate-based systems such as Li₂S—P₂S₅,Li₂S—GeS₂—P₂S₅, Li₃P, LATP (lithium aluminum titanium phosphate) andLiPON, with and without dopants such as Sn, Ta, Zr, La, Ge, Ba, Bi, Nb,etc., ionically-conductive polymers such as those based uponpolyethylene oxide or thiolated materials, LiSICON and NaSICON typematerials, and ionically-conductive oxides and oxyfluorides such aslithium lanthanum titanate, tantalate or zirconate, lithiated andnon-lithiated bismuth or niobium oxide and oxyfluoride, etc., lithiatedand non-lithiated barium titanate and other commonly known materialswith high dielectric strength, and combinations and derivations thereofand or a Garnet, and or LiPON, and or Li-NaSICon, and or Perovskites,and or NASICON structure electrolytes (such as LATP), Na Beta alumina,LLZO. In some embodiments, the SSE coating comprises lithium phosphorussulfide or lithium tin phosphorus sulfide.

In some embodiments, the SSE coating has a thickness of about 60 μm orless, or about 1 nm to about 30 μm, or about 2 nm to about 20 μm, orabout 5 nm to about 10 μm, or about 10 nm to about 1 μm, or about 10-500nm, or about 10-100 nm, or down to about 0.1 nm.

In some embodiments, the porous scaffold is further coated by aprotective coating having a thickness of about 100 nm or less, or about0.1-50 nm, or about 0.2-25 nm, or about 0.5-20 nm, or about 1-10 nm. Insome embodiments, the porous scaffold comprises a (conductive) SSE innercoating and a (non-conductive) passivation/protective outer coatingdisposed on the SSE inner coating. In some embodiments, the porousscaffold comprises a (non-conductive) passivation/protective innercoating and a (conductive) SSE outer coating disposed on thepassivation/protective inner coating. In some embodiments, the porousscaffold comprises alternating, interleaved, and/or multi-layeredstructures of the (conductive) SSE coating and the (non-conductive)passivation/protective coating.

In some embodiments, the protective coating comprises metal oxide, metalnitride, metal carbide, or metal carbonitride. In some embodiments, theprotective coating comprises alumina or titania. In some embodiments,the Lithium based active material may contain mixtures of both aluminaand titania, or multilayers of protective coatings based on alumina andtitania.

In some embodiments, one or both of the protective coating and the SSEcoating are obtained by ALD. In some embodiments, one or both of theprotective coating and the SSE coating are obtained by MLD.

Another aspect of many embodiments of the invention relates to a cathodecomposite layer for a solid state battery, comprising a cathode activematerial mixed with a solid electrolyte material, wherein the cathodeactive material comprises a plurality of cathode particles each coatedby a first protective coating, and wherein the solid electrolytematerial comprises a plurality of SSE particles each coated by a secondprotective coating. In some embodiments, the first protective coatingand the second protective coating are different. For example, the SSEparticles can be coated with TiN for increased conductivity and withAl₂O₃ for protection of the conductive coating, while the cathodeparticles can be coated with just LiPON which may serve both conductiveand protective purposes. Could be multiple layers of multiple layers,such as Al2O3, then TiN, then Al2O3, then TiN for any combination.

In some embodiments, the first protective coating and the secondprotective coating each independently comprises metal oxide, metalnitride, metal carbide, or metal carbonitride. In some embodiments, thefirst protective coating and the second protective coating aredifferent. For example, the SSE particles can be coated with TiN forincreased conductivity and with Al₂O₃ for protection of the conductivecoating, while the cathode particles can be coated with just LiPON whichmay serve both conductive and protective purposes. The coating caninclude multiple layers of multiple materials, such as Al₂O₃, then TiN,then Al₂O₃, then TiN for any combination.

In some embodiments, the first protective coating and the secondprotective coating each independently has an average thickness of about100 nm or less, or about 0.1-50 nm, or about 0.2-25 nm, or about 0.5-20nm, or about 1-10 nm.

In some embodiments, the cathode composite layer further comprises aconductive additive mixed with the cathode active material and the solidelectrolyte material. In some embodiments, the ratio of the cathodeactive material:the solid electrolyte material:the conductive additiveranges from about 5:30:3 to about 80:10:10, or from 1:30:3 to about95:3:2, or up to 97:3:0 if SSE ALD coated cathode active materials areused.

In some embodiments, one or both of the first protective coating and thesecond protective coating are obtained by ALD. In some embodiments, oneor both of the first protective coating and the second protectivecoating are obtained by MLD.

Another aspect of many embodiments of the invention relates to a solidstate battery comprising the cathode composite layer. In someembodiments, the solid state battery further comprises a cathode currentcollector, an anode current collector, an optional lithium metal anodelayer or anode composite layer, an optional separator, and an optionalsolid electrolyte layer.

In some embodiments, the cathode composite layer comprises at leastabout 50 wt. %, or at least about 60 wt. %, or at least about 70 wt. %,or at least about 80 wt. %, or at least about 90 wt. %, of the solidstate battery, based on the total weight of the cathode composite layer,the cathode current collector, the anode current collector, the optionallithium metal anode layer or anode composite layer, the optionalseparator, and the optional solid electrolyte layer.

A further aspect of many embodiments of the invention relates to amethod for improving environmental stability of an SSE particle,comprising depositing a protective coating on the SSE particle by ALD orMLD, wherein the protective coating has a thickness of about 100 nm orless, or about 0.1-50 nm, or about 0.2-25 nm, or about 0.5-20 nm, orabout 1-10 nm.

In some embodiments, the protective coating is obtained by about 1-100ALD cycles, or about 2-50 ALD cycles, or about 4-20 ALD cycles.

In some embodiments, the method further comprises incorporating the SSEparticle coated with the protective coating into a solid state battery,wherein the solid state battery has a first cycle discharge capacitythat is at least about 20% higher, or least about 50% higher, or atleast about 100% higher, or at least about 200% higher, or at leastabout 500% higher than a corresponding solid state battery obtained byincorporating a corresponding SSE particle with no protective coatingunder the same environment (e.g., a non-inert environment comprising anambient O₂ content).

A further aspect of many embodiments of the invention relates to amethod for making a solid electrolyte layer for a solid state battery,comprising depositing a first, SSE coating on a porous scaffold by ALDor MLD, wherein the solid electrolyte layer has a thickness of about 60μm or less, or about 1 nm to about 30 μm, or about 2 nm to about 20 μm,or about 5 nm to about 10 μm, or about 10 nm to about 1 μm, or about10-500 nm, or about 10-100 nm.

In some embodiments, the method further comprises depositing a second,protective coating on the porous scaffold by ALD or MLD, wherein theprotective coating has a thickness of about 100 nm or less, or about0.1-50 nm, or about 0.2-25 nm, or about 0.5-20 nm, or about 1-10 nm.

In some embodiments, the protective coating is obtained by about 1-100ALD cycles, or about 2-50 ALD cycles, or about 4-20 ALD cycles.

In some embodiments, the method further comprises incorporating thesolid electrolyte layer into a solid state battery, wherein the solidstate battery has a first cycle discharge capacity that is at leastabout 20% higher, or least about 50% higher, or at least about 100%higher, or at least about 200% higher, or at least about 500% higherthan a corresponding solid state battery obtained by incorporating acorresponding solid electrolyte layer with no protective coating underthe same environment (e.g., a non-inert environment comprising anambient O₂ content.

An additional aspect of many embodiments of the invention relates toheat treatment of the SSE, independent or in-line with ALD coatingeither before or after ALD coating or in a sequence of repeating steps.The SSE can be heat treated at, for example, about 200°-300° C., orabout 300°-400° C., or about 400°-500° C., or about 500°-600° C., ormore than 600° C. In some embodiments, the SSE particles are first heattreated and then coated with a protective layer by ALD. In someembodiments, the SSE particles are first coated with a protective layerby ALD and then heat treated. In some embodiments, the SSE particles arefirst coated with a first layer by ALD and then heat treated, followedby coating with a second layer by ALD.

An additional aspect of many embodiments of the invention relates to ALDcoating of sulfur onto carbon for Li—S solid state batteries, and/or ALDcoating of sulfur onto SSE to obtain a hybrid SSE-Selectrolyte-electrode. In some embodiments, the SSE particles are firstcoated with sulfur and then coated with an electrically conductivematerial. In some embodiments, the SSE particles are first coated withsulfur and then coated with an electrically conductive material,followed by coating with an SSE layer or a 3-in-1 composite cathodematerial.

An additional aspect of many embodiments of the invention relates to anALD enabled extreme-temperature solid state battery produced usingencapsulated SSE powders.

In an additional aspect of many embodiments of the invention, anSSE-integrated separator can be burned out to be suitable for hightemperature use. An MLD coating may get burned out later to make porousstructures.

An additional aspect of many embodiments of the invention relates to acoated separator comprising one or more MLD coatings on the anode-facingside for silicon anodes.

In an additional aspect of many embodiments of the invention, aseparator substrate comprises porous polymers which has natural flameretardant properties or comprises added flame retardant materials suchas zinc borate or aluminum oxyhydroxide (which may be a naturalbyproduct of low temperature ALD of Al₂O₃) as a way to shut down orquench thermal runaway events that could occur when used in aliquid-containing electrolyte system.

Additional advantages of the disclosure will be set forth in part in thedescription which follows, and in part will be apparent from thedescription, or may be learned by practice of the disclosure. Theadvantages of the disclosure will be realized and attained by means ofthe elements and combinations particularly pointed out in the appendedclaims. It is to be understood that both the foregoing generaldescription and the following detailed description are exemplary andexplanatory only and are not restrictive of the invention, as claimed.

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate one or more exemplary embodimentsof the disclosure and together with the description, serve to exemplifythe principles of the disclosure.

The following detailed description refers to the accompanying drawings.Wherever possible, the same reference numbers may be used in thedrawings and the following description to refer to the same or similarparts. Details are set forth to aid in understanding the embodimentsdescribed herein. In some cases, embodiments may be practiced withoutthese details. In others, well-known techniques and/or components maynot be described in detail to avoid complicating the description. Whileseveral exemplary embodiments and features are described herein,modifications, adaptations and other implementations are possiblewithout departing from the spirit and scope of the invention as claimed.The following detailed description does not limit the invention.Instead, the proper scope of the invention is defined by the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an uncoated active materialparticle.

FIG. 2. is a schematic illustration of a coated active materialparticle.

FIG. 3 is a schematic depiction of certain components of a battery ofcertain embodiments of the present disclosure.

FIGS. 4A and 4B depict an uncoated particle before and after cycling,FIG. 4A depicts the uncoated particle before cycling. FIG. 4B depictsthe uncoated particle after cycling. A comparison of the images reflectsthat the surface of the uncoated material at the end of life is corrodedand pitted and that the lattice has been disrupted relative to thenano-engineered coated material.

FIGS. 5A and 5B depict higher magnification images of the images shownin FIGS. 4A and 4B, showing increased corrosion of the surface (FIG. 4A)and disruption of the lattice (FIG. 4B) in the uncoated image.

FIGS. 6A and 6B are representations of the reciprocal lattice by Fouriertransform, depicting undesirable changes in the bulk material. FIG. 6Adepicts the particle before cycling. The yellow arrows indicate areciprocal lattice, depicting the actual locations of the atoms in thelattice. FIG. 6B depicts a particle of the same material after cycling,showing that the positions of the atoms have been altered.

FIGS. 7A and 7B are graphs of cycle number versus discharge capacity forLi-ion batteries using uncoated active materials or solid-stateelectrolyte. FIG. 7A is a graph of cycle number versus dischargecapacity for a non-gradient HV NMC cathode and graphite anode, cycledunder a 1C/1C rate between 4.2 V and 2.7 V. The line labelled A reflectsthat capacity has fallen to 80% within 200 cycles for the uncoatedactive material. FIG. 7B depicts cycle number versus discharge capacityfor gradient cathode and Si-anode (B) and for mixed cathode (C),depicting that capacity of both has fallen to 80% within 150 cycles.

FIG. 7C depicts test results for full-cell NMC811-Graphite pouch cellswith and without ALD coated Al₂O₃ at a cycling rate of C/3 and voltagewindow of 4.35V-3V.

FIG. 8A depicts test results for full-cell NMC811-Graphite pouch cellswith and without ALD coated Al₂O₃ at a cycling rate of 1C and voltagewindow of 4.35V-3V.

FIG. 8B depicts test results for full-cell NMC811-Graphite pouch cellswith and without ALD coated Al₂O₃ at a cycling rate of 1C and voltagewindow of 4.35V-3V.

FIG. 9A depicts test results for full-cell NCA-Graphite pouch cells withand without ALD coated Al₂O₃ or T_(i)O₂ at a cycling rate of 1C andvoltage window of 4.4V-3V.

FIG. 9B depicts test results full-cell NCA-Graphite pouch cells with andwithout ALD coated Al₂O₃ or T_(i)O₂ at a cycling rate of 1C and voltagewindow of 4.4V-3V.

FIG. 9C depicts the full-cell (NCA/Graphite) capacity at differentdischarge rates from 4.4V-3V relative to Al₂O₃ or T_(i)O₂ coated NCAparticles.

FIG. 10A depicts the half-cell (NMC811/Lithium) capacity at differentdischarge rates from 4.8V-3V vs. Li of an embodiment of the presentdisclosure relative to electrodes made from Al₂O₃ and LiPON coated NMCparticles.

FIG. 10B depicts the half-cell (LMR-NMC/Lithium) capacity at differentdischarge rates from 4.8V-3V vs. Li of an embodiment of the presentdisclosure relative to electrodes made from LiPON coated NMC particles.

FIG. 10C depicts the viscosity vs shear rate for NMC811 with and withoutALD coating.

FIG. 11 is a schematic a hybrid-electric vehicle drive train.

FIG. 12 is a schematic of another embodiment of a hybrid-electricvehicle drive train. Batteries of embodiments of the present disclosuremay be appropriate for use in various types of electric vehiclesincluding, without limitation, hybrid-electric vehicles, plug-in hybridelectric vehicles, extended-range electric vehicles, ormild-/micro-hybrid electric vehicles.

FIG. 13 depicts a stationary power application of batteries of certainembodiments of the present disclosure.

FIG. 14 is a schematic depiction of a process for manufacturing acoating of an embodiment of the present disclosure using atomic layerdeposition.

FIG. 15 is a schematic depiction of a process for manufacturing acoating of an embodiment of the present disclosure using chemical vapordeposition.

FIG. 16 is a schematic depiction of a process for manufacturing acoating of an embodiment of the present disclosure using electron beamdeposition.

FIG. 17 is a schematic depiction of a process for manufacturing acoating of an embodiment of the present disclosure using vacuumdeposition.

FIG. 18 shows atomic layer deposition relative to other techniques.

FIG. 19 shows schematic of an ALD-coated all-solid-state lithium ionbattery.

FIG. 20 shows: (A) schematic of one embodiment of the present inventionthat includes no anode; and (B) schematic of another embodiment of thepresent invention that includes a lithium metal anode.

FIG. 21 shows: (A) schematic of microporous grid, separator, membrane,fabric, planar foam or other semi-rigid, permeable scaffold; (B)schematic of a first ALD coating applied to the scaffold of (A), wherethe first ALD coating represents a solid state electrolyte coatingpossessing a sufficient ionic conductivity with negligible electricalconductivity, whereas the first ALD coating may also be utilized toreduce the pore size of the scaffold of (A); and (C) schematic of asecond ALD coating applied to the first ALD coated scaffold of (B),where the second ALD coating represents an environmental barrier coatingthat does not decrease the ionic conductivity by more than a factor oftwo, nor increase the electrical conductivity relative to (B), whereasthe second ALD coating may also be utilized to reduce the pore size ofthe scaffold of (B).

FIG. 22 shows the ionic conductivity of ALD-coated SSE particles, where<4 nm of Al₂O₃ and 10 nm of TiO₂ neither reduce the ionic conductivity,nor increase the electrical conductivity, of the substrate.

FIG. 23 depicts the environmental barrier performance of varyingthicknesses of ALD coatings applied to SSE particles, where anincreasing performance benefit is observed with increasing thickness.The barrier coating is preventing ingress of H₂O and egress of H₂S fromthe sulfide-based SSE substrate.

FIG. 24 shows discharge capacity of select NCA-based electrochemicalcells showing huge cycling benefit of coated-SEs and coated-NCA. Plotlabels indicate the type of SE, the type of NCA, and the upper cut-offvoltage used, as for example, “P/P 4.5” indicates a cell made withpristine SE, pristine NCA, and an upper cut-off voltage of 4.5 V,whereas “8A/7A 4.2” indicates a cell made with 8 Cycle Al₂O₃-coated SE,7 cycle Al₂O₃-coated NCA, and an upper cut-off voltage of 4.2 V.

FIG. 25 shows coulombic efficiencies for best performing cells showing arising efficiency for all samples. Plot labels indicate the type of SE,the type of NCA, and the upper cut-off voltage used, as for example,“8A/7A 4.2” indicates a cell made with 8 Cycle Al₂O₃-coated SE, 7 cycleAl₂O₃-coated NCA, and an upper cut-off voltage of 4.2 V.

DETAILED DESCRIPTION

Embodiments of the present disclosure comprise nano-engineered coatingsapplied to cathode active materials, anode active materials, orsolid-state electrolyte materials of batteries. Nano-engineered coatingsof embodiments of the present disclosure may inhibit undesirablechemical pathways and side reactions. Nano-engineered coatings ofembodiments of the present disclosure may be applied by differentmethods, may include different materials, and may comprise differentmaterial properties, representative examples of which are presented inthe present disclosure.

FIG. 1 schematically depicts an uncoated active material particle 10 ata scale of 10 nanometer (10 nm). The surface 30 of the active materialparticle 10 is not coated with a nano-engineered coating. Without anycoating, the surface 30 of the active material particle 10 is in directcontact with an electrolyte 15.

FIG. 2 schematically depicts a coated active material particle at ascale of 10 nanometer (10 nm). A coating 20, such as an nano-engineeredALD coating 20, is coated on the surface 30 of the active materialparticle 10. In one embodiment, as shown in FIG. 2, the thickness of thecoating 20 is around 10 nm. In other embodiments, the thickness of thecoating 20 may be of other values, such as a value falls within a rangeof 2 nm to 2000 nm, 2 nm to 20 nm, 5 nm to 20 nm, etc. Thenano-engineered ALD coating 20 may be applied to the active materialparticle 10 used in a cathode or a anode. The nano-engineered coatingdepicted in FIG. 2 may form a thin, uniform, continuous,mechanically-stable coating layer that conforms to surface 30 of theactive material particle. In some alternative embodiments, the coatingcan be non-uniform. It is understood that when a solid electrolyte isused, the coating may also be coated to the solid electrolyte.

In an embodiment of the present disclosure, the surface of cathode oranode active material particle 10 is coated with the nano-engineered ALDcoating 20. Coated cathode or anode active material particles 10 arethen mixed and formed into a slurry. The slurry is applied onto acurrent collector, forming an electrode (e.g., a cathode or an anode).

FIG. 3 is a schematic representation of a battery 100 of an embodimentof the present disclosure. Battery 100 may be a Li-ion battery, or anyother battery, such as a lead acid battery, a nickel-metal hydride, orother electrochemistry-based battery. Battery 100 may include a casing110 having positive and negative terminals 120 and 130, respectively.Within casing 110 are disposed a series of anodes 140 and cathodes 150.Anode 140 may include graphite. In some embodiments, anode 140 may havea different material composition. Similarly, cathode 150 may includeNickel-Manganese-Cobalt (NMC). In some embodiments, cathode 150 may havea different material composition.

As shown in FIG. 3, positive and negative electrode pairs are formed asanodes 140 and cathodes 150 and assembled into battery 100. Battery 100includes a separator and an electrolyte 160 sandwiched between anode 140and cathode 150 pairs, forming electrochemical cells. The individualelectrochemical cells may be connected by a bus bar in series orparallel, as desired, to build voltage or capacity, and disposed incasing 110, with positive and negative terminals 120 and 130. Battery100 may use either a liquid or solid state electrolyte. For example, inthe embodiment depicted in FIG. 3, battery 100 uses solid-stateelectrolyte 160. Solid-state electrolyte 160 is disposed between anode140 and cathode 150 to enable ionic transfer between anode 130 andcathode 140. As depicted in FIG. 3, electrolyte 160 may include aceramic solid-state electrolyte material. In other embodiments,electrolyte 160 may include other suitable electrolyte materials thatsupport ionic transfer between anode 140 and cathode 150.

FIGS. 4A and 4B depict an uncoated cathode active material particle 10,before and after cycling. As depicted in FIG. 4A, the surface of thecathode particle 10 before cycling is relatively smooth and continuous.FIG. 4B depicts the uncoated particle 10 after cycling, exhibitingsubstantial corrosion resulting in pitting and an irregular surfacecontour. FIGS. 5A and 5B depict higher magnification views of particle10 such as those depicted in FIGS. 4A and 4B, showing more irregularsurface following corrosion of uncoated particle 10 as a result ofcycling.

FIGS. 6A and 6B depict the dislocation of atoms in uncoated particle 10.Specifically, FIGS. 6A and 6B are representations of the reciprocallattice. The reciprocal lattice is calculated by Fourier transform ofthe Transmission Electron Microscopy (TEM) image data to depict thepositions of individual atoms in uncoated particle 10. FIG. 6A depictsthe positions of atoms in an uncoated particle 10, before cycling. FIG.6B depicts the positions of atoms in uncoated particle 10, aftercycling. Comparing the atomic positions before and after cycling revealsundesirable changes in the atomic structure of the uncoated particle 10.The arrows in FIG. 6A indicate a reciprocal lattice, depicting theactual locations of the atoms in the lattice. FIG. 6B depicts a particleof the same material after cycling, showing that the positions of theatoms have changed.

FIGS. 7A and 7B demonstrate limitations on cycle life of uncoatedparticles. Uncoated particles typically achieve 200 to 400 cycles andare generally limited to fewer than 400 cycles.

FIG. 7C shows test results for full-cell NMC811-Graphite pouch cellswith and without ALD coated Al₂O₃ at a cycling rate of C/3 and voltagewindow of 4.35V-3V. The horizontal axis shows the cycle number, and thevertical axis shows the C/3 discharge capacity in Ampere hours (Ah). Theactive cathode material used is Lithium Nickel Manganese Cobalt Oxide(NMC), e.g., LiNi_(0.8)Mn_(0.1)CO_(0.1)O₂ (NMC811). The solid line (a)shows results for unmodified NMC811 NMC811 without ALD coating), and thedashed line (b) shows results for NMC811 ALD-coated with Al₂O₃. As shownin FIG. 7C the 0.3C cycle life trends show that the cycle life isenhanced with Al₂O₃ ALD coating. For example, at a given dischargecapacity (e.g., 2.0 Ah), the cycle life for unmodified NMC811 is about675, while the cycle life for NMC811 ALD-coated with Al₂O₃ is about 900.The cycle life increase is attributed to the Al₂O₃ coating on thecathode particles of the cell.

FIG. 8A shows test results for full-cell NMC811-Graphite pouch cellswith and without ALD coated Al₂O₃ at a cycling rate of 1C and voltagewindow of 4.35V-3V. The horizontal axis shows the cycle number, and thevertical axis shows the 1C discharge capacity in Ampere hours (Ah). Theactive cathode material used is Lithium Nickel Manganese Cobalt Oxide(NMC), e.g., LiNi_(0.8)Mn_(0.1) Co_(0.1)O₂ (NMC811). The solid line (a)shows results for unmodified NMC811 (i.e., NMC811 without ALD coating),and the dashed line (b) shows results for NMC811 ALD-coated with Al₂O₃.As shown in FIG. 8A, the 1C cycle life trends show that the cycle lifeis enhanced with Al₂O₃ coating. For example, at a given dischargecapacity (e.g., 1.8 Ah), the cycle life for unmodified NMC811 is about525, while the cycle life for NMC811 ALD-coated with Al₂O₃ is about 725.The cycle life increase is attributed to the Al₂O₃ coating on thecathode particles of the cell.

FIG. 8B shows test results for full-cell NMC811-Graphite pouch cellswith and without ALD coated Al₂O₃ at a cycling rate of 1C and voltagewindow of 4.35V-3V. The horizontal axis shows the cycle number, thevertical axis shows the charge-transfer component of impedance measuredby electrochemical impedance spectroscopy (EIS). Lines (a) and (b) showthe charge-transfer component of the impedance measured by EIS forNMC811 fresh electrodes and electrodes cycled in pouch cells (the samepouch cells as used in obtaining the cycle life test results).Specifically, line (a) shows the charge-transfer component of theimpedance for NMC811 without modification (i.e., NMC811 without ALDcoating) and line (b) shows the charge-transfer component of theimpedance fir NMC811 ALD-coated with Al₂O₃. As shown in FIG. 8B, withALD coating using the charge-transfer component of the impedance isreduced. For example, at cycle number 400, the charge-transfer componentof the impedance is about 22.5 Ohm on line (a) (without. ALD coating),and about 7.5 Ohm on line (b) (with ALD coating). The 1C/−1C cycle lifetrends show that ALD coating can reduce the impedance of the battery.

FIG. 9A shows test results for full-cell NCA-Graphite pouch cells withand without ALD coated Al₂O₃ or T_(i)O₂ at a cycling rate of 1C andvoltage window of 4.4V-3V. The horizontal axis shows the cycle number,and the vertical axis shows the 1C discharge capacity in Ampere hours(Ah). The active cathode material used is Lithium Nickel Cobalt AluminumOxide (NCA), e.g., LiNi_(0.8)Co_(0.15)Al_(0.05)O₂ (NCA), The solid line(a) shows results for unmodified NCA (i.e., NCA without ALD coating),the dashed line (h) shows results for NCA ALD-coated with Al₂O₃, and thedotted line (c) shows results for NCA ALD-coated with T_(i)O₂. As shownin FIG. 9A, the 1C cycle life trends show that the cycle life isenhanced with Al₂O₃ coating or T_(i)O₂ coatings. For example, at a givendischarge capacity (e.g., 1.4 Ah), the cycle life for unmodified. NCA isabout 190, while the cycle life for NCA ALD-coated with Al₂O₃ is about250, and the cycle life for NCA ALD-coated with T_(i)O₂ is about 300.The cycle life increase is attributed to the Al₂O₃ or T_(i)O₂ coatingson the cathode particles of the cell.

FIG. 9B shows test results full-cell NCA-Graphite pouch cells with andwithout ALD coated Al₂O₃ or T_(i)O₂ at a cycling rate of 1C and voltagewindow of 4.4V-3V. The active cathode material used is Lithium NickelCobalt Aluminum Oxide (NCA), e.g., LiNi_(0.8)Co_(0.15)Al_(0.05)O₂ (NCA).The horizontal axis shows the cycle number, the vertical axis shows thecharge-transfer component of the impedance in Ohm, Solid line (a) showsthe charge transfer component of impedance for pouch cells withunmodified NCA (i.e., NCA without ALD coating). Dashed line (b) showsthe charge transfer component of impedance for pouch cells with NCAALD-coated with Al₂O₃. Dotted line (c) shows the charge transfercomponent of impedance for pouch cells with NCA ALD-coated with T_(i)O₂.As shown in FIG. 9B, both lines (b) and (c) show reduced impedance whencompared to line (a). In other words, both ALD coatings (with Al₂O_(:3)and with W₂) reduces the impedance of the battery.

FIG. 9C depicts the full-cell (NCA/Graphite) capacity at differentdischarge rates from 4.4V-3V relative to Al₂O₃ or T_(i)O₂ coated NCAparticles. The horizontal axis shows the discharge C-rate, and thevertical axis shows the discharge capacity in Ah. Solid line (a) showsthe discharge rate capability results for pouch cells with unmodified.NCA (i.e., NCA without ALD coating). Dashed line (b) shows the dischargerate capacity results for pouch cells with NCA ALD-coated with Al₂O₃.Dotted line (c) shows the discharge rate capacity results for pouchcells with NCA ALD-coated with T_(i)O₂. FIG. 9C shows that the Al₂O₃coated particle cell (dashed line (b)) has 19% higher capacity than theuncoated particle cell (solid line (a)) at the 1C rate. FIG. 9C alsoshows that the T_(i)O₂ coated particle cell (dotted line (c)) has 11%higher capacity than the uncoated particle cell (solid line (a)) at 1Crate. The capacity increase is attributed to the Al₂O₃ and T_(i)O₂coatings on the cathode particles in the cells.

Peukert Coefficient is calculated based on the lines (a)-(c) shown inFIG. 9C. The Peukert. Coefficient is 1.15 for NCA without ALD coating,1.04 for NCA ALD-coated with Al₂O₃, and 1.03 for NCA ALD-coated withT_(i)O₂. As shown in FIG. 9C, the ALD coatings (with Al₂O₃, and withT_(i)O₂) help with capacity retention during higher discharge C-rate.For example, at 1C discharge rate, the NCA with ALD coatings (lines (b)and (c)) both show higher discharge capacity as compared with the NCAwithout coating (line (a)).

FIG. 10A depicts the half-cell (NMC811/Lithium) capacity at differentdischarge rates from 4.8V-3V vs. Li of an embodiment of the presentdisclosure relative to electrodes made from Al₂O₃ and LiPON coated NMCparticles. Solid line (a) shows the discharge rate (or specific)capacity results for the half cell with unmodified NMC811 (i.e., NMC811without ALD coating). Dashed line (b) shows the discharge rate capacityresults for the half cell with NMC811 ALD-coated with Al₂O₃. Dashed line(c) shows the discharge rate capacity results for the half cell withNMC811 ALD-coated with UPON. FIG. 10A shows that the Al₂O₃ coatedparticle electrode (line (b)) has higher capacity than the uncoatedparticle electrode (solid line (a)) at nearly all C-rates. The Al₂O₃coated particle has the same capacity at the C/5 rate, 8% highercapacity at the C/3 rate, 50% higher capacity at the 1C rate, and 1,000%higher capacity at the 5C rate. FIG. 10A also shows that the LiPONcoated particle electrode (line (c)) has higher capacity than theuncoated particle electrode (solid line (a)) at all C-rates. The LiPONcoated particle electrode has 6% higher capacity at the C/5 rate, 17%higher capacity at the C/3 rate, 65% higher capacity at the 1C rate, and1,000% higher capacity at the 5C rate. The capacity increase isattributed to the LiPON coating on the cathode particles in the cell.

The Peukert Coefficient is calculated based on the lines (a)-(c) shownin FIG. 10A. The Peukert Coefficient is 1.44 for NMC811 without ALDcoating, 1.08 for NMC811 ALD-coated with Al₂O₃, and 1.06 for NMC811ALD-coated with UPON.

FIG. 10B depicts the half-cell (LMR-NMC/Lithium) capacity at differentdischarge rates from 4.8V-3V vs. Li of an embodiment of the presentdisclosure relative to electrodes made from LiPON coated NMC particles.FIG. 10B shows that the LiPON coated particle electrode (line (b)) hashigher capacity than the uncoated particle electrode (line (a)) at allC-rates. The LiPON coated particle has 5% higher capacity at the C/5rate, 28% higher capacity at the C/3 rate, 234% higher capacity at the1C rate, and 3,700% higher capacity at the 5C rate. The capacityincrease is attributed to the LiPON coating on the cathode particles inthe cell.

FIG. 10C depicts the viscosity vs shear rate for NMC811 with and withoutALD coating. The horizontal axis shows the shear rate, and the verticalaxis shows the viscosity. Lines (a) shows the viscosity vs. shear ratefor unmodified NMC811 (i.e., NMC811 without ALD coating). Lines (b)shows the viscosity vs. shear rate for NMC811 ALD-coated with Al₂O₃. Thehigher viscosity for an equivalent slurry of the unmodified NMC811, aswell as the larger hysteresis between increasing and decreasing shearrates, are indicators of gelation. In other words, with the ALD coating,gelation in a battery can be reduced or prevented.

Embodiments of the present disclosure preferably include a thin coating.Nano-engineered coating 20 may be applied at a thickness between 2 and2,000 nm. In an embodiment, nano-engineered coating 20 may be depositedat a thickness between 2 and 10 nm, 2 and 20 nm, 5 and 15 nm, 10 and 20nm, 20 and 5 nm, etc.

In certain embodiments of the present disclosure, the thickness ofcoating 20 is also substantially uniform. However, uniformity may not berequired for all applications with the nano-engineered coating. In someembodiments, the coating can be non-uniform. As embodied herein, a thincoating 20 is within 10% of the target thickness. In an embodiment ofthe present disclosure, thin coating 20 thickness is within about 5% ofthe target thickness. And, in another embodiment, thin coating thicknessis within about 1% of the target thickness. Certain techniques of thepresent disclosure, such as atomic layer deposition, are readily able toprovide this degree of control over the thickness of coating 20, toprovide a uniform thin coating.

In some embodiments, the thickness of nano-engineered coating 20 mayvary such that the coating is not uniform. For example, coating 20 thatvaries in thickness by more than about 10% of a target thickness ofcoating 20 may be considered as not uniform. Nonetheless, coatingsvarying in thickness by more than 10% are considered to be within thescope of non-uniform coatings of embodiments of the present invention.

As embodied herein, coating 20 may be applied to active material (e.g.,cathode and anode) particles 10 either before forming a slurry of activematerial. Preferably, coating 20 is applied to the particles 10 of anactive material before forming a slurry and pasting to form anelectrode. Similarly, coating 20 may be applied to a solid-stateelectrolyte. In various embodiments, coating 20 is disposed between theelectrode active material (e.g., cathode and/or anode) and electrolyte,whether liquid or solid-state electrolyte, to inhibit side reactions andmaintain capacity of the electrochemical cell.

In an embodiment of the present disclosure, nano-engineered coating 20conforms to the surface of the active material particle 10 or solidstate electrolyte 160. Coating 20 preferable maintains continuouscontact with the active material or solid-state electrolyte surface,filling interparticle and intraparticle pore structure gaps. In thisconfiguration, nano-engineered coating 20 serves as a lithium diffusionbarrier.

In certain embodiments, nano-engineered coating 20 may substantiallyimpede or prevent electron transfer from the active material to SEI. Inalternative embodiments, it may be conductive. Nano-engineered coating20 form an artificial SEI. In an embodiment of the present disclosure,coating 20 limits electrical conduction between the electrolyte and theactive material (e.g., cathode and/or anode) in a way that electrolyte160 does not experience detrimental side reactions, e.g., oxidation andreduction reactions, while permitting ionic transfer between the activematerial and the electrolyte. In certain embodiments, nano-engineeredcoating 20 is electrically conductive and, preferably, has a higherelectrical conductivity than the active material. In other embodiments,nano-engineered coating 20 is electrically insulating, and may have alower electrical conductivity than the active material. The coating 20can be applied to the particles or the electrodes, and can be made of anionic solid or liquid, or covalent bonded materials such as polymers,ceramics, semiconductors, or metalloids.

FIG. 14 is a schematic illustration of a multi-step application processfor forming a coating on an active material (cathode and/or anode) or asolid-state electrolyte. As depicted in FIG. 14, nano-engineered coating20 is applied to surface 30 of particle 10 or solid-state electrolyte160. Coating 20 is formulated and applied so that it forms a discrete,continuous coating on surface 30. Coating may be non-reactive withsurface 30 or may react with surface 30 in a predictable way to form anano-engineered coating on surface 30. Preferably, coating 20 ismechanically-stable, thin, uniform, continuous, and non-porous. Thedetailed description of the process shown in FIG. 14 is discussed later.

In certain embodiments of the present disclosure, nano-engineeredcoating 20 may include an inert material. The present inventors considerseveral formulations of the coated active material particles to beviable. Coatings may be applied to the active material precursorpowders, including: (i) metal oxide; (ii) metal halide; (iii) metaloxyflouride; (iv) metal phosphate; (v) metal sulfate; (vi) non-metaloxide; (vii) olivine(s); (viii) NaSICON structure(s); (ix) perovskitestructure(s); (x) spinel structure(s); (xi) polymetallic ionicstructure(s); (xii) metal organic structure(s) or complex(es); (xiii)polymetallic organic structure(s) or complex(es); (xiv) structure(s)with periodic properties; (xv) functional groups that are randomlydistributed; (xvi) functional groups that are periodically distributed;(xvii) functional groups that are checkered microstructure; (xviii) 2Dperiodic arrangements; and (ixx) 3D periodic arrangements. Metals thatmay form appropriate metal phosphates include: alkali metals; transitionmetals; lanthanum; boron; silicon; carbon; tin; germanium; gallium;aluminum; and indium.

The selection of a suitable coating depends, at least in part, on thematerial of the coating 20 and surface 30 to which it is applied. Notevery one of the above coating materials will provide enhancedperformance relative to uncoated surfaces on every potential activematerial or solid-state electrolyte material. Specifically, the coatingmaterial is preferably selected so that it forms a mechanically-stablecoating 20 that provides ionic transfer while inhibiting undesirableside reactions. Suitable coating materials may be selected in a mannerthat the coating 20 does not react with surface 30 to cause modificationto the underlying surface material in an unpredictable manner. Suitablecoating materials may be selected in a manner that the coating 20 isnon-porous and inhibits the direct exposure to electrolyte of the activematerials.

Persons of ordinary skill in the art understand that undesirablecombinations of coating 20 and surface 30 may be identified by criteriaknown as “Hume-Rothery” Rules (H-R). These rules identify thermodynamiccriteria for when a solute and solvent will react in solid state, givingrise to solid solutions. The H-R rules may help identify whenundesirable reactions between coating 20 and surface 30 may occur. Theserules include four criteria. When the criteria are satisfied,undesirable and uncontrolled reactions between the coating andunderlying active material may occur. Even if all four of the criteriaare satisfied, a particular combination of coating 20 and substrate 30may, nonetheless, be viable, namely, be mechanically-stable andeffective as a coating of the present disclosure. Other thermodynamiccriteria, in addition to the H-R rules, may be required to initiatereaction between the coating 20 and surface 30. The four H-R rules areguidelines. All four of the rules need not be satisfied for sidereactions to take occur, moreover, side reactions may occur even if onlya subset of the rules is satisfied. Nonetheless, the rules may be usefulin identifying suitable combinations of coating 20 and surface 30materials.

First, the atomic radius of the solute and solvent atoms must differ byno more than 15%. This relationship is defined by Equation 4.

$\begin{matrix}{{\% \mspace{14mu} {difference}} = {{\left( \frac{r_{solute} - r_{solvent}}{r_{solvent}} \right) \times 100\%} \leq {15\%}}} & (4)\end{matrix}$

Second, the crystal structures of the solvent and solute must match.

Third, complete solubility occurs when the solvent and solute have thesame valency. A metal dissolves in a metal of higher valency to agreater extent than it dissolves into one of lower valency.

Fourth, the solute and solvent should have similar electronegativity. Ifthe difference in electronegativity is too great, the metals tend toform intermetallic compounds instead of solid solutions.

In general, when selecting coating materials, the H-R rules may be usedto help identify coatings that will form mechanically-stable, thin,uniform and continuous layers of coating that will not dissolve into theunderlying active materials. Hence the more thermodynamically dissimilarthe active material and the coatings are, the more stable the coatingwill likely be.

In certain embodiments, the material composition of the nano-engineeredcoating 20 may meet one or more battery performance characteristics. Incertain embodiments, nano-engineered coating 20 may be electricallyinsulating. In other embodiments, it may not. Nano-engineered coating 20may support stronger chemical bonding with electrolyte surface 30, orcathode or anode active material surface 30, to resist transformation ordegradation of the surface 30 to a greater or lesser degree. Undesirablestructural transformations or degradations may include cracking, changesin metal distribution, irreversible volume changes, and crystal phasechanges. In another embodiment, a nano-engineered coating maysubstantially prevent surface cracking.

Example 1

An embodiment of the present invention was prepared using an aluminacoating on NMC811. The active material, NMC811 powder, was processedthrough atomic layer deposition to deposit a coating of Al₂O₃ on theactive material particles of NMC811. Atomic layer deposition istypically performed at temperatures ranging from room temperature toover 300° C. and at deposition rates that are sufficient to ensure asatisfactory coating while providing good throughput. The NMC811 powderwas coated through the ALD process under conditions sufficient todeposit a 10 nm coating of Al₂O₃ on the NMC active material particles.The coated particles were then used to form a slurry of active materialpaste that was applied to current collectors to form electrodes. Theelectrodes were then made into batteries and tested relative to uncoatedactive material.

The coated material resulted in full-cell cycle life improvements of 33%at a C/3 cycling rate as shown in FIG. 7C and an improvement of 38% at1C cycling rate as shown in FIG. 8A. The coated material also showedimprovement in half-cell rate capability testing at higher voltages, asshown in FIG. 10A. As shown in FIG. 10A, the Al₂O₃ coated particle has8% higher capacity at the C/3 rate, 50% higher capacity at the 1C rate,and 1,000% higher capacity at the 5C rate when compared to the uncoatedmaterial when charged to 4.8V vs. Li.

X-ray Photoelectron Spectroscopy was used to analyze the SEI on thesurface of graphite anodes cycled in pouch cells with modified andunmodified NMC811 cathodes at 1C/−1C. Anode samples were analyzed frompouch cells with 3 different cathodes, uncoated NMC811, NMC811 coatedwith Al₂O₃, and NMC811 coated with T_(i)O₂. Depth profiling resultsshowed that the surface 1 nm of the SEI of the graphite cycled withuncoated NMC811 was enriched in phosphorous, whereas the phosphorouscontent was constant with depth for the graphite samples cycled withAl₂O₃ and T_(i)O₂-coated NMC811. Results also showed that Mn was presentin the SEI of the graphite cycled with uncoated NMC811, but no Mn wasdetected for the graphite samples cycled with Al₂O₃ and T_(i)O₂-coatedNMC811.

Example 2

An embodiment of the present invention was prepared using an aluminacoating on NCA. The active material, NCA powder, was processed throughatomic layer deposition to deposit a coating of Al₂O₃ on the activematerial particles of NCA. Atomic layer deposition is typicallyperformed at temperatures ranging from room temperature to over 300° C.and at deposition rates that are sufficient to ensure a satisfactorycoating while providing good throughput. The NCA powder was coatedthrough the ALD process under conditions sufficient to deposit a 10 nmcoating of Al₂O₃ on the NCA active material particles. The coatedparticles were then used to form a slurry of active material paste thatwas applied to current collectors to form electrodes. The electrodeswere then made into batteries and tested relative to uncoated activematerial.

The coated material resulted in full-cell cycle life improvements of 31%at 1C cycling rate as shown in FIG. 9A. The coated material also showedan improvements in capacity of 19% at the 1C discharge rate, as shown inFIG. 9C.

Example 3

An embodiment of the present invention was prepared using a titaniacoating on NCA. The active material, NCA powder, was processed throughatomic layer deposition to deposit a coating of T_(i)O₂ on the activematerial particles of NCA. Atomic layer deposition is typicallyperformed at temperatures ranging from room temperature to over 300° C.and at deposition rates that are sufficient to ensure a satisfactorycoating while providing good throughput. The NCA powder was coatedthrough the ALD process under conditions sufficient to deposit a 10 nmcoating of T_(i)O₂ on the NCA active material particles. The coatedparticles were then used to form a slurry of active material paste thatwas applied to current collectors to form electrodes. The electrodeswere then made into batteries and tested relative to uncoated activematerial.

The coated material resulted in full-cell cycle life improvements of 57%at 1C cycling rate as shown in FIG. 9A. The coated material also showedan improvements in capacity of 11% at the 1C discharge rate, as shown inFIG. 9C.

Example 4

An embodiment of the present invention was prepared using a LiPONcoating on NMC811. The active material, NMC811 powder, was processedthrough atomic layer deposition to deposit a coating of LiPON on theactive material particles of NMC811. Atomic layer deposition istypically performed at temperatures ranging from room temperature toover 300° C. and at deposition rates that are sufficient to ensure asatisfactory coating while providing good throughput. The NMC811 powderwas coated through the ALD process under conditions sufficient todeposit a 10 nm coating of LiPON on the NMC811 active materialparticles. The coated particles were then used to form a slurry ofactive material paste that was applied to current collectors to formelectrodes. The electrodes were then made into batteries and testedrelative to uncoated active material.

The coated material showed improvement in half-cell rate capabilitytesting at higher voltages. As shown in FIG. 10A, the LiPON coatedparticle electrode has 6% higher capacity at the C/5 rate, 17% highercapacity at the C/3 rate, 65% higher capacity at the 1C rate, and 1,000%higher capacity at the 5C rate when compared to the uncoated materialwhen charged to 4.8V vs. Li.

Example 5

An embodiment of the present invention was prepared using a LiPONcoating on LMR-NMC. The active material, LMR-NMC powder, was processedthrough atomic layer deposition to deposit a coating of LiPON on theactive material particles of LMR-NMC. Atomic layer deposition istypically performed at temperatures ranging from room temperature toover 300° C. and at deposition rates that are sufficient to ensure asatisfactory coating while providing good throughput. The LMR-NMC powderwas coated through the ALD process under conditions sufficient todeposit a 10 nm coating of LiPON on the LMR-NMC active materialparticles. The coated particles were then used to form a slurry ofactive material paste that was applied to current collectors to formelectrodes. The electrodes were then made into batteries and testedrelative to uncoated active material.

The coated material showed improvement in half-cell rate capabilitytesting at higher voltages. As shown in FIG. 10B, the LiPON coatedparticle has 5% higher capacity at the C/5 rate, 28% higher capacity atthe C/3 rate, 234% higher capacity at the 1C rate, and 3,700% highercapacity at the 5C rate when compared to the uncoated material whencharged to 4.8V vs. Li.

In certain embodiments, nano-engineered coating 20 may substantiallyprevent cathode metal dissolution, oxidation, and redistribution. FIG.4A depicts an uncoated active material before cycling. As depicted inFIG. 4A, the surface is nonporous, compact, and uniform. FIG. 4B depictsthe cathode material of FIG. 4A after experiencing cathode metaldissolution, oxidation, and redistribution. The surface appears porous,rough and non-uniform.

In some embodiments, nano-engineered coating 20 may mitigate phasetransition. For example, in an uncoated material, such as that depictedin FIGS. 4B and 5B, cycling of the active material results in a phasetransition of layered-NMC to spinel-NMC. This spinel form has a lowercapacity. This transition is depicted in FIGS. 6A and 6B as a change inposition of the reciprocal lattice points. In a coated material of thepresent disclosure, an alumina coating of Al₂O₃ is applied in athickness of about 10 nm to the cathode active material particles. Uponcycling of the coated active material, no change is seen in the peaks ofthe SEM images. And no degradation of the lattice and of the surfaceafter cycling is observed.

In some embodiments, nano-engineered coating 20 may enhance lithium-ionconductivity and lithium-ion solvation in the cathode. FIGS. 8B and 9Bdepict the cycling performance of with an ALD coating, which exhibits alower charge-transfer component of the impedance than the uncoatedactive material. This is due to Li-ion conductivity remaining high overcycling.

In some embodiments, nano-engineered coating 20 may filter passage ofother atoms and/or molecules on the basis of their sizes. In someembodiments, the material composition of the nano-engineered coating 20is tailored to support size selectivity in ionic and moleculardiffusion. For example, coating 20 may allow lithium ions to diffusefreely but larger cations, such as cathode metals and molecules such aselectrolyte species, are blocked.

In some embodiments, nano-engineered coating 20 includes materials thatare elastic or amorphous. Exemplary coatings 20 include complexes ofaluminum cations and glycerol, complexes of aluminum cations andglucose. In some of those embodiments, coating 20 maintains conformalcontact with active material surfaces even under expansion. In certainembodiments, coating 20 may assist surface 30 to which it is applied inreturning to its original shape or configuration.

In some embodiments, nano-engineered coating 20 includes materials suchthat diffusion of intercalation ions from electrolyte 160 into coating20 has a lower energy barrier than diffusion into active materialuncoated surface 30. These may include an alumina coating of lithiumnickel cobalt aluminum oxide, for example. In some embodiments,nano-engineered coating 20 may facilitate free intercalationion-transport across the interface from coating into active materialthereby bonding with active material surfaces 30.

In some embodiments, nano-engineered coating 20 includes materials thatundergo a solid state reaction with the active material at surface 30 tocreate a new and mechanically-stable structure. Exemplary materialsinclude a titania coating of lithium-nickel-cobalt-aluminum-oxide.

In some embodiments, electrolyte 160 may be chemically stable andcoating 20 may include alumina or titania coating 20 on lithiumtitanate.

A non-exhaustive listing of materials that may be used in thenano-engineering coating 20 may include: Al₂O₃, ZnO, TiO₂, SnO₂, AlF₃,LiPON, Li_(x)FePO₄, B₂O₃, Na_(x)V₂(PO₄)₃, Li₁₀GeP₂S₁₂, LaCoO₃,Li_(x)Mn₂O₄, Alucone, Rh₄(CO)₁₂, Mo₆Cl₁₂, B₁₂H₁₂, Li₇P₃S_(ii), P₂S₅,Block co-polymers, zeolites.

One of ordinary skill in the art would appreciate that any of theaforementioned exemplary material compositions of nano-engineeredcoating 20 may be used singularly or combined with one another, or withanother material or materials to form composite nano-engineered coating20.

Batteries of embodiments of the present disclosure may be used formotive power or stationary power applications. FIGS. 11 and 12 areschematic diagrams depicting an electric vehicle 1100 having a battery100 of an exemplary embodiment of the present disclosure. As depicted inFIG. 11, vehicle 1100 may be a hybrid-electric vehicle. An internalcombustion engine (ICE) 200 is linked to a motor generator 300. Anelectric traction motor 500 is configured to provide energy to vehiclewheels 600. Traction motor 500 may receive power from either battery 100or motor generator 300 through a power inverter 400. In someembodiments, motor generator 300 may be located in a wheel hub anddirectly linked to traction motor 500. In some embodiments, motorgenerator 300 may be directly or indirectly linked to a transmissionconfigured to provide power to wheels 600. In some embodiments,regenerative braking is incorporated in vehicle 1100 so that motorgenerator 300 receives power from wheels 600 as well. As shown in FIG.12, a hybrid-electric vehicle 1100 may include other components, such asa high voltage power circuit 700 configured to control battery 100. Thehigh voltage power circuit 700 may be disposed between the battery 100and the inverter 400. Hybrid-electric vehicle 1100 may include agenerator 800 and a power split device 900. The power split device 900may be configured to split the power from the internal combustion engine200 into two parts. One part of the power may be used to drive thewheels 600, another part of the power may be used to drive the generator800 to generate electricity using the power from the internal combustionengine 200. The electricity generated by generator 800 may be stored inbattery 100.

As depicted in FIGS. 11 and 12, an embodiment of the present disclosuremay be used in battery 100. As depicted in FIGS. 11 and 12, battery 100may be a lithium-ion battery pack. In other embodiments, battery 100 maybe of other electrochemistries or multiple electrochemistries. See Dhar,et al., U.S. Patent Publication No. 2013/0244063, for “Hybrid BatterySystem for Electric and Hybrid Electric Vehicles,” and Dasgupta, et al.,U.S. Patent Publication No. 2008/0111508, for “Energy Storage Device forLoads Having Variable Power Rates,” both of which are incorporatedherein by reference in their entireties, as if fully set forth herein.Vehicle 1100 may be a hybrid electric vehicle or all-electric vehicle.

FIG. 13 depicts a stationary power application 1000 powered by battery100. Facility 1200 may be any type of building including an office,commercial, industrial, or residential building. In an exemplaryembodiment, energy storage rack 1300 includes batteries 100. Batteries100 may be nickel cadmium, nickel-metal hydride (NiMH), nickel zinc,zinc-air, lead acid, or other electrochemistries, or multipleelectrochemistries. Energy storage rack 1300, as depicted in FIG. 13,may be connected to a distribution box 1350. Electrical systems forfacility 1200 may be linked to and powered by distribution box 1350.Exemplary electrical systems may include power outlets, lighting, andheating, ventilating, and air conditioning systems.

Nano-engineered coating 20 of embodiments of the present disclosure maybe applied in any of several ways. FIGS. 14, 15, 16, and 17 depictschematically several alternative application methods. FIG. 14 depicts aprocess for coating surface 30 of a cathode active material, an anodeactive material, or a solid-state electrolyte material surface usingatomic layer deposition (ALD). As depicted in FIG. 14, the processincludes the steps of: (i) surface 30 is exposed to a precursor vapor(A) that reacts with surface 30; (ii) the reaction between surface 30and precursor vapor (A) yields a first layer of precursor molecules onsurface 30; (iii) modified surface 30 is exposed to a second precursorvapor (B); (iv) the reaction between surface 30 and precursor vapors (A)& (B) yields a second layer, bonded to the first layer, comprisingcompound A_(X)B_(Y), A_(X), or B_(Y).

In this disclosure, atomic layer deposition and molecular layerdeposition are used synonymously and interchangeably.

In some embodiments, nano-engineered coating 20 is applied by molecularlayer deposition (e.g., coatings with organic backbones such as aluminumglyceride). Surface 30 may be exposed to precursor vapors (A) and (B) byany of a number of techniques, including, but not limited to, adding thevapors to a chamber having the electrolyte therein; agitating a materialto release precursor vapors (A) and/or (B); and/or agitating a surfaceof electrolyte to produce precursor vapors (A) and/or (B).

In certain embodiments, atomic layer deposition is preferably performedin a fluidized-bed system. Alternatively or additionally, surface 30 maybe held stationary and precursor vapors (A) and (B) may be allowed todiffuse into pores between surface 30 of particles 10. In someembodiments, surface 30 may be activated, e.g., heated or treated with acatalyst to improve contact between the electrolyte surface andprecursor vapors. Atomic layer deposition is typically performed attemperatures ranging from room temperature to over 300° C. and atdeposition rates that are sufficient to ensure a satisfactory coatingwhile providing good throughput. In other embodiments, atomic layerdeposition may be performed at higher or lower temperatures, e.g., lowerthan room temperature (or 70° F.) or temperatures ranging over 300° C.For example, atomic layer deposition may be performed at temperatures25° C. to 100° C. for polymer particles and 100° C. to 400° C. formetal/alloy particles.

In another embodiment, surface 30 may be exposed to precursor vapors inaddition to precursor A and/or B. For example, a catalyst may be appliedby atomic layer deposition to surface 30. In other embodiments, catalystmay be applied by another deposition technique, including, but notlimited to, the various deposition techniques discussed herein.Illustrative catalyst precursors include, but are not limited to, one ormore of a metal nanoparticle, e.g., Au, Pd, Ni, Mn, Cu, Co, Fe, Pt, Ag,Ir, Rh, or Ru, or a combination of metals. Other catalysts may include,for example, PdO, NiO, Ni₂O₃, MnO, MnO₂, CuO, Cu₂O, FeO, Fe₃O₄, SnO₂.

In another embodiment, atomic layer deposition may include any one ofthe steps disclosed in Reynolds, et al., U.S. Pat. No. 8,956,761, for“Lithium Ion Battery and Method for Manufacturing of Such a Battery,”which is incorporated herein by reference in its entirety as if fullyset forth herein. In other embodiments, atomic layer deposition mayinclude the step of fluidizing precursor vapor (A) and/or (B) beforedepositing nano-engineered coating 20 on surface 30. Kelder, et al.,U.S. Pat. No. 8,993,051, for “Method for Covering Particles, EspeciallyBattery Electrode Material Particles, and Particles Obtained with SuchMethod and A Battery Comprising Such Particle,” is incorporated hereinby reference in its entirety, as if fully set forth herein. Inalternative other embodiments, any precursor (e.g., A or B) can beapplied in a solid state.

In another embodiment, repeating the cycle of introducing first andsecond precursor vapors (e.g., A, B of FIG. 14) may add a secondmonolayer of material onto surface 30. Precursor vapors can be mixedbefore, during, or after the gas phase.

Exemplary preferred coating materials for atomic layer depositioninclude metal oxides, self-assembling 2D structures, transition metals,and aluminum.

FIG. 15 depicts a process for applying coating 20 to surface 30 bychemical vapor deposition. In this embodiment, chemical vapor depositionis applied to a wafer on surface 30. Wafer is exposed to a volatileprecursor 50 to react or decompose on surface 30 thereby depositingnano-engineered coating 20 on surface 30. FIG. 15 depicts a hot-wallthermal chemical vapor deposition operation that can be applied to asingle electrolyte or multiple electrolytes simultaneously. Heatingelement is placed at the top and bottom of a chamber 60. Heatingenergizes precursor 50 or causes it to come into contact with surface30. In other embodiments, nano-engineered coating 20 may be applied byother chemical vapor deposition techniques, for example plasma-assistedchemical vapor deposition.

FIG. 16 depicts a process for applying coating 20 to surface 30 byelectron beam deposition. Surface 30 and additive 55 are placed invacuum chamber 70. Additive 55 is bombarded with an electron beam 80.Atoms of additive 55 are converted into a gaseous phase and precipitateon surface 30. Electron beam 80 is distributed by an apparatus 88attached to a power source 90.

FIG. 17 depicts a process for applying coating 20 to surface 30 by usingvacuum deposition (VD). Nano-engineered coating 20 is applied in ahigh-temperature vacuum chamber 210. Additives 220, stored in areservoir 230, is supplied into the high-temperature vacuum chamber 210,where additives 220 evaporate and condensate onto surface 30. A valve240 controls the flow of additives 220 into chamber 210. A pump 250controls vacuum pressure in chamber 210.

Any of the aforementioned exemplary methods of applying nano-engineeredcoating 20 to surface 30 may be used singularly, or in combination withanother method, to deposit nano-engineered coating 20 on surface 30.While one portion of surface 30 may be coated with a nano-engineeredcoating 20 of a certain material composition, another portion of surface30 may be coated with a nano-engineered coating 20 of the same ordifferent material composition.

Applications of nano-engineered coating 20 to an electrolyte surface arenot limited to the embodiments illustrated or discussed herein. In someembodiments, nano-engineered coating 20 may be applied in a patternedformation to an electrolyte surface providing alternate zones with highionic conductivity and zones of high elasticity or mechanical strength.Exemplary material selections for nano-engineered coating 20 of someembodiments include POSS (polyhedral oligomeric silsesquioxanes)structures, block co-polymer structures, 2D and 3D structures thatself-assemble under an energy field or minimum energy state, such ase.g., glass free energy minima. NEC can be randomly or periodicallydistributed in these embodiments.

Other application techniques may also be used to apply nano-engineeredcoating other than those illustrated or discussed herein. For example,in other embodiments, nano-engineered coating application processes mayinclude laser deposition, plasma deposition, radio frequency sputtering(e.g., with LiPON coatings), sol-gel (e.g., with metal oxide,self-assembling 2D structures, transition metals or aluminum coatings),microemulsion, successive ionic layer deposition, aqueous deposition,mechanofusion, solid-state diffusion, doping or other reactions.

Embodiments of the present disclosure may be implemented in any type ofbattery including solid-state batteries. Batteries can have differentelectrochemistries such as for example, zinc-mercuric oxide, zinc-copperoxide, zinc-manganese dioxide with ammonium chloride or zinc chlorideelectrolyte, zinc-manganese dioxide with alkaline electrolyte,cadmium-mercuric oxide, silver-zinc, silver-cadmium, lithium-carbon,Pb-acid, nickel-cadmium, nickel-zinc, nickel-iron, NiMH, lithiumchemistries (like e.g., lithium-cobalt oxide, lithium-iron phosphate,and lithium NMC), fuel cells or silver-metal hydride batteries. Itshould be emphasized that embodiments of the present disclosure are notlimited to the battery types specifically described herein; embodimentsof the present disclosure may be of use in any battery type.

For example, the above disclosed nano-engineered coating 20 may beapplied to lead acid (Pb-acid) batteries. In a typical lead acidbattery, the production of reaction at the electrodes is lead sulfate.On charging lead sulfate is converted to PbO₂ on the positive electrodeand to spongy lead metal at the negative electrode.

While the PbO₂ and lead are good semiconductors, lead sulfate is anon-conductor. Similarly on the negative electrode side, PbSO₄ is anon-conductor. The product of charging, namely, Pb is a good metallicconductor. As the electrodes are discharged, PbO₂ on the anode and Pb onthe cathode are converted to lead sulfate and the resistance increasesconsiderably. Since the realizable power is dependent on the resistance,any increase in resistance would be undesirable. This problem has beenpartially solved in the negative electrode by adding conductingadditives which keep the resistances low despite the formation ofinsulating lead sulfate. For example high surface area conductingcarbons can be added to the anode mix. This addition accomplishes twoimportant activities. By virtue of the huge surface area increase, theeffective operating current density is kept low and thus the cathodeelectrode polarization is minimized. In addition, the presence of carbonin the cathode mix improves the effective conductivity of the mix duringcharge or discharge. The choice of the type of carbon is important suchthat the additive does not influence the hydrogen over potential. If itdoes, there will be undesirable gassing issues. As a corollary, if theright carbon is used, it can postpone hydrogen evolution that minimizesgas evolution. At the potential the negative electrode of a lead acidbattery operates, the carbon is cathodically protected so that it doesnot corrode or disappear. This is of great importance in the functioningof the lead acid battery.

In addition, there is a finite change in the volumes of lead sulfate andlead dioxide and lead metal. This increase in volume due to theformation of lead sulfate is a major concern for the lead acid battery.Volume changes produce stresses on the electrodes and the promote growthof the electrodes. Since lead sulfate is only sparingly soluble in theacid medium, the growth becomes somewhat permanent. With every cycle ofcharge and discharge, the transformation of lead sulfate to lead dioxideand lead metal is supposed to be reversible. Owing to efficiency issues,the transformation process becomes less and less reversible as the cellages. The growth cannot be reversed by normal battery operation.

Another consequence of the lead sulfate growth is the increase in theresistance of the electrodes. The adhesion between the current collectorand the active material is weakened by the presence of lead sulfate.Internal stresses also flex the grid/active material interface, leadingto potential delamination. As the adhesion between the substrate and theactive material becomes weaker, electrolyte enters the crevices andstarts attacking the substrate leading to lead sulfate growth. Once thisoccurs, the resistance continues to increase.

As the demands of the auto industry for more powerful and low costbattery increase, it is essential to look for other means of reducingthe module/cell resistance. The resistance of the anode appears to be alogical choice to attack the problem. Adopting a similar technique onthe anode side of the electrode in addition to in the cathode side maynot work well. This is mainly due to the potential at which the anodeworks. Also after about 60-70% charge input, the thermodynamics of theanode chemistry dictates that oxygen evolution be accompanied with theactive material charging. At this anode potential and with nascentoxygen evolution, carbon addition to decrease the resistance would notbe useful as the carbon will be oxidized. Any other additive to improvethe conductivity of the anode will likely fail because of the potentialas well as the aggressively acidic environment.

One way to solve these problems is to use atomic layer depositiontechnique to coat the carbon particles so that the particles wouldimpart conductivity to the mix without getting oxidized or decomposed atthe anodic potential they face.

Consistent with the disclosed embodiments, active materials may bedesigned to facilitate their functions according to their location andgeometry within a battery pack. The functions that may be built in theelectrodes include: chemical composition tailored to the electrodefunction (e.g., slower/faster reaction rates), weight of the electrodesto have a gradient according to the earth gravity field, gradient inelectrode porosity to allow for compensating in different reaction ratesat the center of the electrode stack and at the corners.

In addition, as the demands of the auto industry for more powerful andlow cost battery increase, it is desirable to look for methods forkeeping lead sulfate growth as low as possible so that high powercapabilities can be achieved. From the cost point of view, currently,lead acid battery system is the most viable choice for the stop startapplications.

Electrode growth, corrosion of the active materials, corrosion of thesubstrates, corrosion of the additives etc. do exist in otherrechargeable battery systems and in certain fuel cells as well. Many ofthe active materials used in these systems either undergo volumechanges, or are attacked by the environment they are exposed to, orcorroded by the product of the reaction. For example, the metal hydrideelectrodes used in Nickel Metal Hydride batteries or the zinc electrodeused in Nickel zinc or zinc air batteries, or the iron electrode used inNi—Fe batteries all undergo corrosion as well as gradual irreversiblevolume changes. The decrepitation of the hydride electrode, thecorrosion of cobalt and aluminum from the hydride alloy and theunder-cutting of the bonding between the substrate and active materialsare a few of the failure mechanisms present in nickel metal hydridecells. Similarly, “shape change” and irreversible growth contribute tothe failure of Nickel zinc and zinc air batteries. Corrosion of ironelectrode, gassing and poisoning of the positive electrode fromcontaminants leached out from the iron electrode are things to beconcerned about in Ni—Fe batteries. All the nickel based positiveelectrodes also undergo volume changes and subsequent soft shorts andactive material fall out. In all these systems it is also difficult toincorporate carbon additive in the positive electrode to improve theconductivity and reduce corrosion since carbon will be oxidized at theoperating potentials of these positive electrodes. Fuel cells based onalkaline or acidic polymer electrolyte also have similar oxidationissues. In these cases carbon is used to enhance conductivity, increasesurface area and provide a means to distribute the reactant gases. Inthe case of alkaline fuel cells, even at the cathode, carbon becomesundesirable. In spite of being at the cathodic potentials where carbonis supposed to be stable, oxygen reduction produces peroxide ions whichreact with the carbon additive and the substrates and undermine theirstability.

Consistent with the disclosed embodiments, ALD/MLD techniques may beused to coat the positive and negative active materials with materials(e.g., nano-engineered coating materials) that keep the fundamentalcurrent producing reactions intact while containing the formation,growth and corrosion. Films produced by ALD and MLD are very thin andhave sufficient amounts of nano pores to keep the reactions going whileprotecting the active materials. For example, atomic layer depositiontechnique may be used to coat the carbon particles so that the particleswould impart conductivity to the mix without getting oxidized ordecomposed at the anodic potential they face.

Consistent with the disclosed embodiments, active materials may becoated with protective coatings to facilitate their functions with thegrowth potential of active materials kept in containment. ALD/MLDcoatings have been proven to be effective in preventing/postponing SEIlayer formation in the lithium battery without affecting theperformance. The ALD/MLD coatings may also be applied to otherbatteries, including most of the commercial rechargeable battery systemssuch as Lead Acid batteries and Nickel metal hydride batteries.

To coat the lead acid battery (or other battery) active materials,suitable precursors are selected to effectively coat the ALD coatings onthe positive and negative active materials of the battery system (e.g.,the lead acid battery system).

Consistent with the disclosed embodiments, electrodes may be built withdifferent coatings applied to which using a novel technique that doesnot unduly increase the cost of the electrode materials but retain thefunctionalities.

The inventors are faced with a program of reducing the undue growth ofactive materials with a protective coating and evaluating itseffectiveness in real life situations inside a battery. To solve theproblem, the disclosed embodiments of applying the nano-engineeredcoatings to the active materials essentially reduce the overallresistance of the positive electrode and result in bulk addition ofconducting additive to the cathode active materials. This promotesachievement of higher specific power values. The advantages of thedisclosed embodiments may include lower resistance of electrodes,uniform heat and uniform chemical reaction rate/off gassing processesdistribution within a pack and higher specific power realization. Cyclelife can also be enhanced.

In some existing batteries, coating may be applied to negativeelectrodes. For positive electrodes, nano carbon additives and singlewalled and multi walled nano carbon additives have been used. These,however, are expensive additives whose life expectancies need to beimproved. Consistent with the disclosed embodiments, a low costprotective coating may be applied to the active materials of a lead acidbattery (and other batteries) as well as to the additives.

Consistent with the disclosed embodiments, in lead acid batteries, anoxidation prevention coating may be deposited on carbon particles usingatomic layer deposition (ALD). ALD coatings is a one of the more recenttechniques developed to provide coatings on surfaces for various uses.This technique can be used to coat battery (e.g., lead acid battery,lithium ion battery, and any other suitable battery) active materialsand achieve significant improvement in the performance and cycle life ofthe batteries. These coatings can also provide a certain degree ofprotection from thermal runaway situations. What is more remarkableabout this technique is that the coatings are only under 0.1 microns,usually in the nano scale.

Some advantage of the disclosed embodiments include lowering theresistance of the Positive Active Material (PAM) and Negative ActiveMaterial (NAM) electrodes, lowering the overall resistance of themodule, improving the specific power, and enhancing the cycle life.

FIG. 18 shows atomic layer deposition relative to other techniques. Asshown in FIG. 18, atomic layer deposition and molecular layer depositionuse particles having sizes ranging from about 0.05 microns to about 500microns and can produce films having thicknesses ranging from about0.001 microns to about 0.1 microns. Chemical vapour deposition techniquemay use particles having sizes ranging from about 1 micron to about 80microns, and can produce films having thicknesses ranging from about 0.1microns to about 10 microns. Other techniques, such as pan coating, drumcoater, fluid bed coating, spray drying, solvent evaporation, andcoacervation may use particles having sizes ranging from about 80microns to over 10000 microns, and can produce films having thicknessesranging from about 5 microns to about 10000 microns. The ranges shown inFIG. 18 are schematic and illustrative only, and are not to exact scale.

ALD is a gas phase deposition technique with sub nano-meter control ofcoating thickness. By repeating the deposition process, thicker coatingscan be built as desired. These coatings are permeable to the transportof ions such as hydrogen, lithium, Pb-acid, etc., but do not allowlarger ions. This is important in preventing unwanted side reactionsfrom occurring. The disclosed embodiments may include coating carbonparticles with ALD coatings and using the ALD coated carbon particles asan additive to the Positive Active Material (PAM) mix. While the carbonaddition will improve the overall conductivity of the mix, oxidation ofthe carbon due to the electrode potential and evolution of oxygen willcease to occur thanks to the coating. The PAM/solution interface willonly see the ALD coating on the electrode surface and corrosion willcease to occur.

Consistent with the disclosed embodiments, ALD/MLD coatings can becoated as discrete clusters or as continuous films depending uponwhether access to other ions in solution is desired or not. Control ofthe open areas between the clusters can be controlled by the size of theclusters. In other words, the coating functions as nano filters on theactive materials but still provide access to the reaction sites. In thecase of ALD coatings on carbon particles on PAM oxygen molecules beingmuch larger than the cluster pores, the carbon substrate will not beoxidized while other electrochemical reactions will still be allowed toproceed.

The inventors have conducted tests on the ALD coatings. Tests resultsshow that with the ALD coatings, batteries have enhanced cycle life andreduced resistance. In addition, in the batteries with the ALD coatings,phase transition is inhibited, and gelling or gelation is hampered orinhibited. Gelation occurs in a battery when there is excessive waterand heat in a mixture. The mixture turns into a gel, which does notflow. The gel can clog up the internal pipes inside the batterymanufacturing plant. Clogged pipes needs to be cleaned or replaced. Bycoating the active materials and/or the solid state electrolyte of thebattery, gelation issue can be inhibited. Test results shown in FIG. 10Cdemonstrates that the ALD coating can prevent or reduce gelation.

One aspect of the present disclosure involves removing LiOH species fromNMC particle surfaces. Another aspect of the present disclosure alsoinvolves controlling the interaction between particle surfaces andbinder additives such as PVDF or PTFE. A further aspect of the presentdisclosure involves controlling the surface acidity or basicity or pH.The present disclosure further includes an aspect involving particularsolvents like water or NMP, or particular binder additives such as PVDFor PTFE. The disclosed ALD coating is of particular importance formaterials with Ni content greater than 50% of total Ni, Mn, Co, Al, andother transition metals.

One aspect of the present disclosure involves in some order, in somecombination, a layer for controlled water absorption or adsorption, orreduced absorption or adsorption, a layer for active material structurestability, a layer to provide atoms for doping other layers, a layer toprovide atoms for doping the active material, and/or a layer forreducing electrolyte oxidation or controlled electrolyte decompositionand SEI information.

One aspect of the present disclosure involves enhanced battery thermalstability during events of nail penetration, short-circuit, crush, highvoltage, overcharge, and other events. By coating the anode, cathode,solid-state electrolyte, a certain combination of these, or all ofthese, battery thermal stability can be improved The present teachingsare applicable to batteries for supporting various electrical systems,e.g., electric vehicles, facility energy storage, grid storage andstabilization, renewable energy sources, portable electronic devices andmedical devices, among others. “Electric vehicles” as used in thisdisclosure includes, but not limited to, vehicles that are completely orpartially powered by electricity. The disclosed embodiments result inimproved specific power performance, which will pave the way for leadacid batteries (coated with the nano-engineered coating) to be used forelectric vehicles, hybrid electric vehicles, or plug-in hybrid electricvehicles.

Surface coatings and high throughput vapor deposition methods areinstrumental for producing tailored compositions comprising stabilizedsubstrates for all-solid-state secondary batteries at high efficiencyand low cost. Examples of vapor deposition techniques can includechemical vapor deposition (CVD), physical vapor deposition (PVD), atomiclayer deposition (ALD), molecular layer deposition (MLD), vapor phaseepitaxy (VPE), atomic layer chemical vapor deposition (ALCVD), ionimplantation or similar techniques. In each of these, coatings areformed by exposing a moving powder or substrate to reactive precursors,which react either in the vapor phase (e.g., in the case of CVD) or atthe surface of the substrate (e.g., as in ALD and MLD). These processescan be augmented by the incorporation of plasma, pulsed or non-pulsedlasers, RF energy, and electrical arc or similar discharge techniques tofurther compatibilize the coating/encapsulation process with thesubstrate(s).

Solid-state electrolyte (SSE) layers can be produced using SSEsubstrates of varying compositions that initially have a sufficientionic conductivity (on the order of 10⁻⁴-10⁻² S cm⁻¹) to potentiallyallow solid state secondary batteries comprising these materials toexhibit initial properties with equivalent performance toliquid-electrolyte comprised systems. Lithium conducting sulfide-based,phosphide-based or phosphate-based systems such as Li₂S—P₂S₅,Li₂S—GeS₂—P₂S₅, Li₃P, LATP (lithium aluminum titanium phosphate) andLiPON, with and without dopants such as Sn, Ta, Zr, La, Ge, Ba, Bi, Nb,etc., ionically-conductive polymers such as those based uponpolyethylene oxide or thiolated materials, LiSICON and NaSICON typematerials, and or a Garnet, and or LiPON, and or Li-NaSICon, and orPerovskites, and or NASICON structure electrolytes (such as LATP), NaBeta alumina, LLZO and even ionically-conductive oxides and oxyfluoridessuch as lithium lanthanum titanate, tantalate or zirconate, lithiatedand non-lithiated bismuth or niobium oxide and oxyfluoride, etc.,lithiated and non-lithiated barium titanate and other commonly knownmaterials with high dielectric strength, and similar materials,combinations and derivations thereof may all be suitable as SSEsubstrates in the present invention. These systems are described in U.S.Pat. No. 9,903,707 and U.S. application Ser. No. 13/424,017, the entirecontents of which are incorporated herein by reference. These materialsmay also be combined with anode and cathode materials (usingconventional blending or a variety of milling techniques) prior toelectrode fabrication, or otherwise used as conductive additivesthroughout components of a solid state, liquid-electrolyte or hybridsolid-liquid electrolyte battery cell.

An small subset of the aforementioned materials or compositions can alsobe deposited using vapor deposition techniques (e.g. doped and undopedLiPON, LLTO, LATP, BTO, Bi₂O₃, LiNbO₃, and others) such as CVD, PVD, andleast frequently even ALD, which are pathways to incorporate thebenefits of solid electrolyte materials as compatibilizing coatingsbetween electrode and electrolyte (liquid, solid, hybrid liquid-solid orsemi-solid glassy or polymeric) interfaces. Examples of such coatingsand materials are described in U.S. application Ser. No. 13/651,043 andU.S. Pat. No. 8,735,003, the entire contents of which are incorporatedherein by reference. In vapor deposition processes such as ALD and MLD,the particles are contacted with two or more different reactants in asequential manner, and said reactant contacting steps may preferentiallybe self-limiting or not, self-terminating or not, or operated inconditions designed to promote or prevent the limitation ornon-limitation thereof. In addition, any two sequential self-limitingreactions may occur most efficiently at different temperatures, whichwould require heating or cooling of any suitable reactor between cyclesteps in order to accommodate each step and thereby capture the value ofsuch efficiency. Ultimately to manufacture coatings and coated materialsat lowest cost using vapor deposition techniques, it is commonlyunderstood that high throughput systems that provide a transport meansfor the substrate, which maintaining control over the vapor depositionprecursors, will provide the lowest cost per unit of produced material.Such systems are increasingly referred to as “spatial” techniques,relative to “temporal” techniques ascribed to batch systems that at mostprovide a recirculation means for each substrate to be coated and employtime-based processing steps. Spatial ALD is one such technique thatemploys an entirely different sequence than a Temporal ALD process.Example processing approaches and apparatuses suitable for Spatial ALDon particles and roll-to-roll systems for moving sheets, foils, films orwebs are described in U.S. application Ser. Nos. 13/169,452, 11/446,077,and 12/993,562, and U.S. Pat. No. 7,413,982, the entire contents ofwhich are incorporated herein by reference.

For solid state energy storage systems to become cost-competitive withtheir commercial liquid electrolyte-based counterparts, themanufacturability and processability of such materials in commonequipment is desirable. Thus it is important to allow sub-componentand/or device fabrication to occur in simply a moisture-controlledenvironment such as a dry room, rather than an oxygen andmoisture-controlled environment such as a glove box. An encapsulationcoating on moisture-sensitive and/or oxygen-sensitive substrates canprovide a means for such manufacturability, which would allow saidmaterials to be “drop-in” ready in conventional processing equipment. Amethod for utilizing ALD to stabilize the interfaces betweenpre-fabricated SSE layers and pre-fabricated electrodes is described inU.S. application Ser. No. 14/471,421, which is an alternative approachto the ALD-coating of cathode powders interfaced with SSE materialsdescribed in U.S. application Ser. No. 13/424,017. However, neither ofthese teachings achieve the objective of being able to safely orreliably handle SSE particulate materials prior to the formation of sucha bulk SSE layer or being able to intermix such materials that areintended to be as homogeneously co-located or co-mingled with theelectroactive powders in the electrode layer. The ALD barrier applied inU.S. application Ser. No. 14/471,421 is preferentially polished toensure direct contact between the electrolyte layer and the electrodelayer, and as such the ALD process seems to have primarily served thepurpose of filling void spaces at these interfaces, rather than to serveas a physicochemical barrier film to protect the interfaces immediatelycontacting one another. In addition, the present invention leads tounexpected results relative to the teachings of U.S. application Ser.No. 13/424,017, in which 10 Al₂O₃ ALD cycles applied to the interfacesof the electroactive cathode particles began to cause a reduction inperformance in solid state batteries. In contrast, using the presentinvention net interfaces comprising a total number of ALD cyclesexceeding 10 and sometimes 20 to 40 still provide increased performanceimprovements relative to pristine electrode and SSE powders and theirinterfaces. By way of example, FIG. 24 shows how ˜15 ALD cycles at theinterface of NCA and LPS SSE powder at both 4.2 V and 4.5 V top ofcharge exhibit an approximate 10-fold increase in capacity relative topristine materials charged to the same voltage in the same cellconfigurations. Depending on growth rates and ALD conditions, thisinterfacial layer may be upwards of 7.5 nm in thickness. This is alsodifferent from the teachings of U.S. Pat. No. 8,993,051, in which >2 nmAl₂O₃ ALD films were shown to begin to decrease the performance ofconventional Lithium-ion batteries that use liquid electrolytes.

The encapsulated or passivated SSE materials that are suitable for usein conventional slurry-based coating approaches used in Li-ion batterymanufacturing would reduce the cost and complexity of manufacturingsolid state batteries. Until now, no such encapsulation coating has beendeveloped or demonstrated that can provide such stability to anionically-conductive SSE material to render it suitable for processingin a conventional dry room, even as coatings used as barrier films onsulfide-based host materials in other fields. By way of example, U.S.Pat. No. 7,833,437 teaches how the ALD method can be used to encapsulateZnS-based electroluminescent phosphor materials to render themimpervious to oxygen and moisture, but tens of nanometers of coatingwere required, which would tend to be too thick and non-conductive,rendering such coating thicknesses unsuitable for use on SSE materials.

Many conventional SSE materials produced using solid state synthesistechniques (e.g. thermally-treating Li₂S, P₂S₅ and GeS₂ precursorpowders in appropriate stoichiometry under appropriate conditions) tendto be in size ranges of 10-250 μm in diameter, and furtherpost-processing techniques (e.g. ball milling and other common methods)have been deployed to reduce the size of SSE materials sometimes from0.5-20 μm, and sometimes provide reductions to 5 μm in maximum diameter.However, the SSE particles may be made smaller through bottom-upsynthesis approaches, for example, via a modification of the flame sprayprocess described in U.S. Pat. No. 7,211,236 that is designed to produceoxygen-free materials such as sulfides or preferentially a process thatat least partially incorporates a plasma spray process as described inU.S. Pat. No. 7,081,267, or similar processes; and the encapsulationprocess of this invention can be performed directly in-line after suchSSE particles are produced using an apparatus described in U.S. patentSer. No. 13/169,452. More generally, particles to be encapsulated inaccordance with the invention can be of any type produced using knownionically-conductive particle manufacturing processes. The encapsulationprocess of this invention can be performed as part of an integratedmanufacturing process which includes a manufacturing step to produce theparticle followed directly or indirectly by the coating process of theinvention. Ultimately since encapsulated SSE materials are commonlyintended to be used as part of a bulk SSE layer interposed between anodeand cathode, as well as in the form of a homogeneous blend ofelectroactive materials, binders, conductive additives or othermaterials, it is understood that the encapsulated SSE materialsdescribed herein may have a different coating composition or thicknesswhen used in the bulk electrolyte layer, the portion of the electrolytelayer that is in close proximity to the anode or cathode layers but notat the interface, the actual interfaces in contact with the electrolyteand each electrode, the SSE material that is blended with electroactivepowders, a layer of SSE material that interfaces with either electrodeand its respective current collector, or any other useful location inwhich an encapsulated SSE will provide value to the produced device. Byway of example, when used with cathode particles, with or without ALDcoatings, of 5 μm in mean diameter with a relatively narrow sizedistribution, such as may be found in a cell designed for high energydensity, a homogeneous blend of this material paired with anALD-encapsulated 100 nm SSE powder derived using a plasma spray approachmay provide for better uniform distribution and interstitial void spaceaccumulation than would an encapsulated 5 μm SSE powder. In other cases,a flame or plasma spray derived 50-500 nm electroactive particle may bedesirable, such as for cells designed for high power applications, andhomogenizing these particles may be substantially easier when pairedwith 20-30 μm encapsulated SSE powders.

The optimal ALD thickness and composition of each encapsulating specieshas been determined to be substantially different in differentcircumstances. One processes and apparatus that may be suitable for suchhomogenization is a fluidized bed reactor, described in U.S. Pat. No.7,658,340 and U.S. application Ser. No. 13/651,977, further advantagedby the use of vibration, stirring or micro-jet incorporation to expeditehomogenization, described in U.S. Pat. No. 8,439,283. Thermal treatmentsthat have been shown to be advantageous to SSE substrate materials andALD coated cathode particles taught in U.S. application Ser. No.13/424,017 can also be employed during such a dry homogenization step.SSE materials and ALD-coated electroactive materials can be thermallytreated in an inert or reducing atmosphere, at 200° C.-600° C.,preferably 300° C.-550° C., for a period of time, from 1 to 24 hours forexample, to obtain the desired properties (typically degree ofhomogeneity, conductivity, interfacial composition, diffusion ofcoating/substrate species to form solid, glassy-solid or otherpseudo-solid solutions, sulfidation of the materials, crystallite sizemodification, or other phenomenon understood to be beneficial to theperformance of solid state batteries).

Said ALD coating encapsulating the SSE powder co-located with a cathodepowder may benefit from Ti³⁺ or Ti⁴⁺ based ALD coatings found in TiO₂,TiN, Ti₃N₄, oxynitrides, TiC, etc., and synergistic incorporation ofsulfur to form titanium sulfide or titanium phosphide phases. Similarly,GeO₂ containing ALD coatings may be particularly beneficial for cathodematerials due to the potentially higher stability of germanium in thepresence of cathode materials in solid state batteries. As nearly theentire periodic table can be deposited using ALD, these are two of manycations that can be considered useful in SSE materials, and theirspecific reference in no way limits the applicability of any othersuitable materials.

One feature of this invention relies on the ability to depositcontrolled quantities of material on the surfaces of SSE particles orSSE surfaces, where the typical conductivity of the coating materials isknown to be insufficient for use as an electrolyte material, for examplethose with conductivities less than 1×10⁻⁶ S cm⁻¹. This is derived fromthe typical increase in protective benefits provided by an ALD coatingof increasing thickness, and the typical decrease in usability of thesubstrate in its intended role with a similarly increasing thickness. Asthis invention further allows the SSE materials to be solvent castablein layers, there is a feature of tailoring the composition of aplurality of layers by utilizing coated SSE materials with differentcoating properties, to thereby produce a gradient when these pluralityof layers are viewed in aggregate (for instance an air-protective layer,a sacrificial layer for casting, and an interface layer for improvingbattery performance and multiples. Similarly, if the materials aregas-phase deposited directly onto a moving substrate using a spraydrying, plasma spray process, etc., downstream-deposited materials mayhave a different set of compositions or properties than those depositedupstream.

Any of the particles made in such a preliminary particle-manufacturingstep can be directly produced in a particle production process using anconvenient continuous flow process, can be delivered into a weighbatching system with a metering valve (rotary airlock or similar), andcan then enter into the process described in the present invention.

Molecular layer deposition (MLD) processes are conducted in a similarmanner, and are useful to apply organic or inorganic-organic hybridcoatings. Examples of MLD methods are described, for example, in U.S.Pat. No. 8,124,179, which is incorporated herein by reference in itsentirety.

ALD and MLD techniques permit the deposition of coatings of about 0.1 to5 angstroms in thickness per reaction cycle, and thus provide a means ofextremely fine control over coating thickness. Thicker coatings can beprepared by repeating the reaction sequence to sequentially depositadditional layers of the coating material until the desired coatingthickness is achieved.

Reaction conditions in vapor phase deposition processes such as ALD andMLD are selected mainly to meet three criteria. The first criterion isthat the reagents are gaseous under the conditions of the reaction.Therefore, temperature and pressure conditions are selected such thatthe reactants are volatilized when the reactive precursor is broughtinto contact with the powder in each reaction step. The second criterionis one of reactivity. Conditions, particularly temperature, are selectedsuch that the desired reaction between the reactive precursor and theparticle surface occurs at a commercially reasonable rate. The thirdcriterion is that the substrate is thermally stable, from a chemicalstandpoint and from a physical standpoint. The substrate should notdegrade or react at the process temperature, other than a possiblereaction on surface functional groups with one of the reactiveprecursors at the early stages of the process. Similarly, the substrateshould not melt or soften at the process temperature, so that thephysical geometry, especially pore structure, of the substrate ismaintained. The reactions are generally performed at temperatures fromabout 270 to 1000 K, preferably from 290 to 450 K.

Between successive dosings of the reactive precursors, the particles canbe subjected to conditions sufficient to remove reaction products andunreacted reagents. This can be done, for example, by subjecting theparticles to a high vacuum, such as about 10⁻⁵ Torr or greater, aftereach reaction step. Another method of accomplishing this, which is morereadily applicable for industrial application, is to sweep the particleswith an inert purge gas between the reaction steps. This sweep withinert gas can be performed while the particles are being transportedfrom one reactor to the next, within the apparatus. Dense- anddilute-phase techniques, either under vacuum or not, are known to besuitable for the pneumatic conveying of a wide variety of industriallyrelevant particles that would be well-served by the functionalizationprocess described herein.

The starting powder can be any material which is chemically andthermally stable under the conditions of the deposition reaction. By“chemically” stable, it is meant that the powder particles do notundergo any undesirable chemical reaction during the deposition process,other than in some cases bonding to the applied coating. By “thermally”stable, it is meant that the powder does not melt, sublime, volatilize,degrade or otherwise change its physical state under the conditions ofthe deposition reaction.

The applied coating may be as thin as about 1 angstrom (corresponding toabout one ALD cycle), and as thick as 100 nm or more. A preferredthickness range is from 2 angstroms to about 25 nm.

An All-Solid-State Lithium-ion Battery (1913) and an ALD CoatedAll-Solid-State Lithium-ion Battery (1915) are shown in FIG. 19. TheAll-Solid-State Lithium-ion Battery (1913) comprises an Anode CompositeLayer (1901) which comprises a combination of Anode Active Material(1905), Conductive Additive (1906), and Solid Electrolyte (1907), whichis in contact with an Anode Current Collector (1904). Similarly, aCathode Composite Layer (1903) comprises a combination of Cathode ActiveMaterial (1908), Conductive Additive (1906), and Solid Electrolyte(1907), which is in contact with a Cathode Current Collector (1909). Thetwo layers, the Anode Composite Layer (1901) and the Cathode CompositeLayer (1903), are separated by a Solid Electrolyte Layer (1902) whichcan be entirely composed of Solid Electrolyte (1907). Solid Electrolyte(1907) may be composed of one solid electrolyte material or a pluralityof materials, for example as an ALD coating of a solid electrolytematerial onto a different solid electrolyte material, or two layers ofsolid electrolyte materials, or a coated electrolyte (e.g., coated withceramic, electrolyte, conductive materials), or a combination of solidelectrolyte materials (e.g., two different solid electrolytes—one incontact with anode and one in contact with cathode—each optionallyhaving a different ALD coating on it).

As show in FIG. 19, the All-Solid-State Lithium-ion Battery (1913) canbe transitioned to an ALD Coated All-Solid-State Lithium-ion Battery(1915) through the Atomic Layer Deposition (1914) process in whichatomic layer deposition is used to encapsulate the particles of AnodeActive Material (1905), Conductive Additive (1906), and SolidElectrolyte (1907), and/or Cathode Active Material (1908). In someembodiments, Anode Active Material (1905) has Anode ALD Coating (1910),Conductive Additive (1906) has Conductive Additive ALD Coating, SolidElectrolyte (1907) has Solid Electrolyte ALD Coating (1911), and CathodeActive Material (1908) has Cathode ALD Coating (1912). In someembodiments, Anode Active Material (1905), Conductive Additive (1906),and Solid Electrolyte (1907), and Cathode Active Material (1908) havethe same coating in which Anode ALD Coating (1910), Conductive AdditiveALD Coating, Solid Electrolyte ALD Coating (1911), and Cathode ALDCoating (1912) are the same material applied by ALD (but can bedifferent layers/thicknesses). In another embodiment Anode ALD Coating(1910), Conductive Additive ALD Coating, Solid Electrolyte ALD Coating(1911), and Cathode ALD Coating (1912) are different coatings (atdifferent thicknesses).

The ratios of Anode Active Material (1905):Conductive Additive(1906):Solid Electrolyte (1907) and Cathode Active Material(1908):Conductive Additive (1906):Solid Electrolyte (1907) can rangewidely depending on the desired performance of the cell. Similar toelectrodes for conventional liquid electrolyte batteries, solid-stateelectrodes can be a composite made of active material (AM), conductiveadditive (CA), and electrolyte. The active material, such as LiCoO₂ fora cathode and/or graphite for an anode, stores the lithium movingthrough the battery during charging and discharging. The conductiveadditive, which is commonly a carbon material such as acetylene black orcarbon nanotubes, acts as a means to ensure rapid electron transportthrough the electrode to the current collector. Electrolyte is necessarywithin the electrode to ensure rapid ion transport into and out of theelectrode as a whole. Different from liquid electrolyte batteries,however, solid state batteries utilize the solid electrolyte as bothseparator and electrolyte, which simplifies the system as compared toliquid electrolyte batteries which requires a polymer-based separatorbetween the electrodes. Moreover, having the solid electrolyte act asthe separator ensures intimate contact with the electrodes as well as anunbroken path for ion conduction. Furthermore, due to the physicalseparation of the electrodes by the solid electrolyte, reactions ateither electrode would not indirectly cause problems at the otherelectrode, such as with batteries utilizing a Mn-containing cathodematerial which has been found to cause parasitic losses at the graphitebased anode via indirect contact through the liquid electrolyte.

Another important benefit of a solid-state battery is the capability toconstruct a “lithium-free” battery in which there is no anode compositeor bulk lithium metal foil to act as an anode to form a lithium battery.In a Li-free battery, a cell is constructed such that during the firstcharging cycle, metallic lithium is electroplated in between the solidelectrolyte and the thin film current collector. While this designfollows the concept of a Li-metal battery which is capable of highenergy density. Such battery is safer as there is no excess Li with canlead to dangerous conditions if punctured. This design leads tosignificant improvement in realizable energy density resulting from highloading of active materials in the cathode, a virtual elimination of thecurrent collector and separator, and a high packing efficiency due tothe solid structure.

In designing a battery from the ground up, one should ensure the highestrelative weight of active material in order to maintain the highestpossible energy density. Ideally, a battery would comprise solely of acathode with 100% active material and an anode with 100% activematerial. However, because active materials are typically designed forlithium storage and not ion/electron conduction, it is desirable togenerate a composite electrode with conductive additive and solidelectrolyte to ensure target performance metrics through fasterelectron/ion conduction. While excess proportions of both the conductiveadditive and solid electrolyte can be used to increase powder densitywith faster electron/ion transport, doing so may reduce the relativeratio of active material within an electrode thereby reducing thehighest energy density the battery can achieve.

Ratios of active material:solid electrolyte:conductive additive canrange widely, preferably from about 5:30:3 to about 80:10:10, or fromabout 1:30:3 to about 95:3:2, for both anode and cathode composites, orup to 97:3:0 if SSE ALD coated cathode active materials are used. In onecase can have a lithium battery with a lithium anode. In another casecan have lithium-free battery where initial cycle deposits lithium forlater cycling. In some embodiments, powders of pristine active materialand/or coated active material are used to prepare a slurry withprecursors for the solid electrolyte materials, which are run through aslurry spray pyrolysis system. In other words, rather than blendingfinished particles, one can create composite materials and then apply afinal protective coating.

In some embodiments of the battery described herein, the compositecathode can comprise a high voltage lithium manganese nickel oxidespinel (e.g., LiMn_(1.5)Ni_(0.5)O₄ (LMNO)) with a maximum capacity of147 Ah kg⁻¹ when cycled between 3.5-5.0 V having an average voltage of4.7 V, yielding a maximum energy density of a lithium battery based onLMNO to be 690 Wh kg⁻¹. In some embodiments, the composite cathodefurther comprises a sulfur based solid electrolyte (e.g., Li₁₀SnP₂S₁₂(LSPS)) with high ionic conductivity up to 10⁻² S cm⁻¹, and a conductiveadditive (e.g., Super C65) which has demonstrated good results with LMNOin liquid electrolyte batteries. LMNO has a theoretical density of 4.45g cm⁻³ from which an estimated realizable pellet density of 3.4 g cm⁻³can be derived from previous demonstrations of similar materials.Assuming a complete filling of the remaining porosity in the pellet withthe LSPS having density 2.25 g cm⁻³, an 87:13 weight ratio of LMNO andLSPS can be obtained. For the solid-state composite battery, 82% of thetheoretical energy density can be achieved as follows:

0.87×0.99×0.95÷1.09=82%

where 0.95 is from packing efficiency which is often achieved in pouchcells, 0.99 is from 1 wt % of CA, and 1.09 from 9 μm of LSPS electrolytewith respect to a 110 μm total thickness of battery cathode,electrolyte, and anode layers. As a result, the energy density of thesolid-state Li battery is projected to be 565 Wh kg⁻¹ from:

690 Wh kg⁻¹×82%=565 Wh kg⁻¹.

Because LMNO maintains its high capacity of 147 Ah kg⁻¹ at high rate,using a nominal cycling rate of 2C/2C for charge and discharge a minimumpower density of the all-solid-state Li-ion battery was calculate to beover 1 kW kg⁻¹:

565 Wh kg⁻¹×2C h⁻¹=1130 W kg⁻¹.

Table 1 shows a comparison between one example of a proposedall-solid-state Li-ion battery and a state-of-the-art Li-ion battery.The typical state-of-the-art Li-ion battery contains numerous inactivematerials such as porous polymer separator, metal foil currentcollectors, and packaging and safety devices that do not contribute toenergy storage. These inactive components are responsible for 37% of thetotal weight of a battery cell (see Table 1). In addition, eachelectrode contains up to 12.5% polymer binder which brings the highestachievable energy density even lower. The solid-state composite batterydescribed herein would allow the use of electrolyte and currentcollectors in thin film form, eliminating most of the inactive weight.Moreover, high loading of active materials in the electrode allowed bythe solid-state composite electrode design and high packing efficiencydue to the solid structure further improve the realizable energy densityof the all-solid-state described herein.

TABLE 1 Comparison between the proposed all-solid-state battery and astate-of- the-art battery described by Argonne National Labs. WeightPercentage (%) All-Solid-State Battery Component Liquid SOA compositeBattery Composite Cathode 41 90 Composite Anode 16 <1 Separator 2 0Electrolyte 18 <5 Aluminum Current Collector 2 <0.2 Copper CurrentCollector 4 <0.2 Other components including 17 5 safety devices TotalWeight 100 100

The following examples are provided to illustrate coating processesapplicable to making the compositions of the invention. These examplesare not intended to limit the scope of the inventions. All parts andpercentages are by weight unless otherwise indicated.

Working Examples Example 1 Material Processing

ALD Coating of SE Materials: 10 g of pristine SE (LPS, NEI Corp.)samples were loaded into a standard stainless steel fluidized bedreactor under Ar atmosphere and connected to a PneumatiCoat PCR reactorto conduct ALD. For proof-of-concept, low quantities of SE powder wereALD-coated using a fluidized bed system instead of a high throughputsystem. The sample was placed under minimum fluidization conditions inwhich 100 sccm of N₂ was flowed for the entirety of the ALD process. ALDwas performed at 150° C. to prevent the SE from any additional heattreatment and reactivity during the ALD process. Due to the potentiallyreactive nature of the SE with the precursors TMA/H₂O for Al₂O₃ andTiCl₄/H₂O₂ for TiO₂ a timed schedule was used to apply 4, 8, and 20layers of Al₂O₃ and TiO₂, respectively. For Al₂O₃ coatings the TMA wasapplied for 15 minutes and the H₂O for 7.5 minutes, with 10 minutevacuum purging steps between. For TiO₂ coatings the TiCl₄ was appliedfor 10 minutes and the H₂O₂ for 20 minutes, with 15 minute vacuumpurging steps between.

ALD Coating of Electrode Samples 1: 1.5 kg of Lithium Nickel ManganeseOxide (LMNO) powder (SP-10, NEI Corp.) was processed through the PCThigh throughput reactor to produce 250 g sample batches of 2, 4, and 8cycle Al₂O₃ coated materials. During this high throughput process,Trimethylaluminum (TMA) is used as Precursor A and Deionized Water (H₂O)is used as the second precursor (Precursor B). Each precursor is appliedin series using the PCT patented semi-continuous reactor system inappropriate quantities as determined using the specific surface area andquantity of particles being processed. Similarly, 2, 4, and 8 cycle TiO₂ALD coated LMNO samples were generated using Titanium Tetrachloride(TiCl₄) as Precursor A and Hydrogen Peroxide (H₂O₂) as Precursor B. Allsamples were handled in air before being dried in a vacuum oven at 120°C. and moved into the Argon filled glovebox for later processing.

ALD Coating of Electrode Materials 2: 1 kg of pristine Lithium NickelCobalt Aluminum Oxide (NCA) powder (NCA-7150, Toda America) wasprocessed through the PCT high throughput reactor to produce 250 gsamples of 2, 4, 6, and 7 cycle Al₂O₃ coated materials. Similarly, 2, 4,and 8 cycle TiO₂ ALD coated NCA samples were generated using TitaniumTetrachloride (TiCl₄) as Precursor A and Hydrogen Peroxide (H₂O₂) asPrecursor B. All samples were handled in air before being dried in avacuum oven at 120° C. and moved into the Argon filled glovebox forlater processing.

Example 2 Material Characterization

Conductivity of SE Materials: Electrolyte pellets were formed by coldpressing 200 mg of SE powder to 8 tons, using a polytetrafluoroethylene(PTFE) die (φ=0.5 in) and Titanium metal rods for both pelletization andas current collectors for both working and counter electrodes. Li foil(MTI, 0.25 mm thick) is then attached to both sides of the electrolyteand the cell configuration secured. Electrochemical impedance analysis(EIS) is performed using a Solartron 1280 Impedance analyzer at afrequency range of 1 MHz to 2 Hz and an AC Amplitude of 10 mV. Allpressing and testing operations are carried out in an Ar-filled glovebox.

Cyclic Voltammetry of SE Materials: Electrolyte pellets were formed bycold pressing 200 mg of SE powder to 8 tons, using apolytetrafluoroethylene (PTFE) die (φ=0.5 in) and Titanium metal rodsfor both pelletization and as current collectors for both working andcounter electrodes. Li foil (MTI, 0.25 mm thick) is then attached to oneside of the electrolyte and cyclic voltammetry performed on a Solartron1280 using cutoff voltages of −0.5 V and 5.0 V for 5 cycles with a scanrate of 1 mV/s. All pressing and testing operations are carried out inan Ar-filled glove box.

Air/Moisture Stability of SE Materials: 1 g of SE was loaded into asmall fluidized bed reactor in an Ar-filled glovebox and connected tothe PCR Reactor with a Residual Gas Analyzer (RGA) (Vision 2000-P, MKSInstruments). All atmospheric conditions were carefully removed from thesystem prior to testing in order to minimize any non-intendedair/moisture from entering the reactor. Once sufficient vacuumconditions were met, the reactor was placed under vacuum for 5 minutesto remove the Ar. Following purging, the reactor was exposed toair/moisture through the application of dry compressed air at a flowrate equivalent of a 5 torr increase in pressure while vaporized H₂O wasapplied at varying pressure.

Electrochemical Cell Fabrication and Testing: Composite cathodes wereprepared by mixing LMNO powder or NCA powder as the active material(AM), solid electrolyte (SE) for fast lithium ion conduction, andacetylene black (MTI) as a conductive additive (CA) for electronconduction at a weight ratio of 1:30:3 for the AM:SE:CA, respectively.The SE and CA were mixed thoroughly using a mortar and pestle, followedby mixing-in of the AM. SE pellets were formed by pressing 100 mg of SEpowder to 0.2 tons, using a polytetrafluoroethylene (PTFE) die (φ=0.5in) and Titanium metal rods for both pelletization and as currentcollectors for both working and counter electrodes. A 5 mg layer of thecomposite cathode material was then spread evenly on one side of the SElayer and the two-layer cell was pelletized by cold pressing (8 tons)for 1 min. Li foil (MTI, 0.25 mm thick) was then attached to theopposite side of the electrolyte and hand pressed. Galvanostaticcharge-discharge cycling took place at cut off voltages of 2.5-4.5 V and2.5-5.0 V for the LMNO, and 2.5-4.2 V and 2.5-4.5 V for the NCA to lookat differences in stability imparted by ALD coatings. Cycling wasperformed at a current of C/20 for the first ten cycles followed by C/10for the remaining cycles. All pressing and testing operations arecarried out in an Ar-filled glove box.

Example 3 Results

ALD was performed on the SEs to make them more air/moisture tolerant aswell as to observe any electrochemical effects. Using Al₂O₃ and TiO₂ asthe coating chemistries applied to the SEs, three different levels ofcoating were targeted—4 cycles (2 nm), 8 cycles (4 nm), and 20 cycles(10 nm) of each ALD coating with 1 cycle roughly equivalent to about0.1-1.0 nm thick shell around particles of solid electrolyte. For theseinitial trials TMA and H₂O were used as the precursors as they are themost commonly accepted precursors for applying ALD to any substratepowder. Initial consideration was given to using TMA and IsopropylAlcohol (IPA) precursors to avoid H₂O exposure to the powders, but inthe interest of producing these coatings on a commercial scale the mostviable high-throughput-capable candidates should be investigated. Forthe TiO₂ coating TiCl₄ and H₂O₂ were used. Initial consideration wasgiven to avoiding the use of H₂O₂ due to its strong likelihood to reactnegatively with the SE due to the general sensitivity of theelectrolyte. Similar to the justification for H₂O as the secondprecursor for applying Al₂O₃, it was decided to use the most wellunderstood and the least complex method for proof-of-concept.

Observation of the conductivity of these ALD-coated samples are shown inFIG. 22(A). Lower number of cycles of Al₂O₃ exhibited an increase inconductivity. However, higher number of cycles of Al₂O₃ coated samplesexhibited a decrease in conductivity. This is likely because highernumber of cycles of ALD would increase resistance when coating with aceramic, but lower number of cycles would result in improved materialproperties due to the protection obtained from Al₂O₃ in which the thinshell imparts no excess impedance because it is thin. Interestingly,unexpected results were found for TiO₂ coated SE samples—higher numberof ALD cycles also exhibited a significant increase in conductivity forTiO₂ coated SE. Specifically, a nearly two orders of increase inconductivity was observed for the 20 cycle TiO₂ sample as compared tothe pristine electrolyte, as shown in FIG. 22(B).

The capability of ALD to reduce the SE sensitivity to air and moisturewhile at the same time improving cell performance was investigated.Stabilizing the SE to air allows a realistic commercialization path inwhich SEs can be handled and used without the need for an inertenvironment, making them drop-in capable for existing batterymanufacturing equipment. FIG. 23 shows the Pristine and coated SEreaction when being exposed to air and moisture. It was observed thatAl₂O₃ coated SEs yielded a significantly reduced concentration of H₂Sgas. A strong correlation was observed in which increasing cycles ofAl₂O₃ deposited on SEs results in a two-fold improvement: a reducedoverall concentration of H₂S gas output as well as a delayed reactiontime. These data are an excellent indication of the positive benefitscapable of being obtained by using ALD on the SEs.

High-capacity NCA was used to realize the extraordinary benefit to theall-solid-state cells through ALD-coatings. For proof-of-concept, only 7Cycle Al₂O₃ coated NCA is shown. However, as can be seen in FIGS. 24 and25, testing of the 7 Cycle Al₂O₃-coated NCA with the panel of availablecoated SEs is showing tremendous benefit from ALD. Here, it is observedthat cells made with pristine SE and pristine NCA did not perform well,achieving only a first cycle discharge capacity of less than 5 mAh/g forboth 4.2 V and 4.5 V cut-off voltages. However, upon the introduction ofAl₂O₃-coated SEs, a significant improvement in cycling behavior wasachieved. Multiple beneficial effects can be distilled fromelectrochemical cycling such as a much higher achievable reversibledischarge capacity and high voltage cycling. For example, when comparingthe P/7A 4.2, 4A/7A 4.2, and 8A/7A 4.2 curves in FIG. 24 and improvementin first cycle discharge capacity from 5 mAh/g, to 57 mAh/g, to 100mAh/g, respectively, is observed. Similarly, when comparing both 4A/7A4.2 and 4A/7A 4.5 curves and 8A/7A 4.2 and 8A/7A 4.5 curves, we see notonly a capacity increase due to the higher cut-off voltage, but also asustained capacity with the higher cut-off voltage indicating that theAl₂O₃ coatings on the SE and NCA allow stabilized higher voltagecycling. If high voltage can be sustained by the Al₂O₃ coatings onmaterial then the overall energy density that can be achieved by thissystem increases dramatically.

As used herein, the singular terms “a,” “an,” and “the” include pluralreferents unless the context clearly dictates otherwise. Thus, forexample, reference to a compound can include multiple compounds unlessthe context clearly dictates otherwise.

As used herein, the terms “substantially,” “substantial,” and “about”are used to describe and account for small variations. When used inconjunction with an event or circumstance, the terms can refer toinstances in which the event or circumstance occurs precisely as well asinstances in which the event or circumstance occurs to a closeapproximation. For example, the terms can refer to less than or equal to±10%, such as less than or equal to ±5%, less than or equal to ±4%, lessthan or equal to ±3%, less than or equal to ±2%, less than or equal to±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or lessthan or equal to ±0.05%.

Additionally, amounts, ratios, and other numerical values are sometimespresented herein in a range format. It is to be understood that suchrange format is used for convenience and brevity and should beunderstood flexibly to include numerical values explicitly specified aslimits of a range, but also to include all individual numerical valuesor sub-ranges encompassed within that range as if each numerical valueand sub-range is explicitly specified. For example, a ratio in the rangeof about 1 to about 200 should be understood to include the explicitlyrecited limits of about 1 and about 200, but also to include individualratios such as about 2, about 3, and about 4, and sub-ranges such asabout 10 to about 50, about 20 to about 100, and so forth.

Preferred embodiments of the present invention relate generally toelectrochemical cells that include: Embodiment 1: anionically-conductive coating for a cathode active material, an anodeactive material, or a solid state electrolyte for use in a battery. Thecoating includes a layer of coating material disposed on a surface ofthe cathode active material, the anode active material, or the solidstate electrolyte of the battery; the layer of coating materialincluding one or more of a metal, polymetallic or non-metal: (i) oxide,carbonate, carbide or oxycarbide, nitride or oxynitride, oroxycarbonitride; (ii) halide, oxyhalide, carbohalide or nitrohalide;(iv) phosphate, nitrophosphate or carbophosphate, or (v) sulfate,nitrosulfate, carbosulfate or sulfide.

The anionic combination descriptions above may represent from 0.1% to99.5% of each combined anion, or 1% to 95%, 5% to 15%, 35% to 65%, orabout 50%. By way of example, a polymetallic oxynitride may berepresented as nitrogen-niobium-titanium-oxide, where the oxygen tonitrogen ratio may be 0.1:99.9, 5:95, 35:65 or 50:50; a metalnitrophosphate may include LiPON, AlPON or BPON. A non-metal oxide mayinclude phosphorous oxide. A polymetallic oxide may includelithium-lanthanum-titanium-oxide or lithium-lanthanum zirconium-oxide,the latter of which may be deposited with alternating layers of Li—O,La—O, Zr—O. A polymetallic phosphate,lithium-aluminum-titanium-phosphate, may be deposited using alternatinglayers of TiPO₄, Al₂O₃ and Li₂O, or LiPO₄, TiO₂, AlPO₄, or Li₂O, TiPO₄and AlPO₄, in any order, ratio or preferred composition.

The layer or layers of coating material, may be preferentially similaror different for any cathode active material, anode active material orsolid state electrolyte material onto which each layer of coatingmaterial is disposed, and may be coated prior to the fabrication andformation of the electrochemical cell, or produced in situ after anyformation step of the electrochemical cell itself.

Each layer of coating material may be further described as havingstructures that include (vi) amorphous; (vii) olivine; (viii) NaSICON orLiSICON; (ix) perovskite; (x) spinel; (xi) polymetallic ionicstructures, and/or (xii) structures with preferentially periodic ornon-periodic properties. The preferred embodiments of coating layersthat combine one or more of the coating materials (i)-(v) withstructures that can be described by one or more of (vi)-(xii), mayfurther possess: (xiii) functional groups that are randomly distributed,(xiv) functional groups that are periodically distributed, (xv)functional groups that are checkered microstructure, and may include(xvi) 2D periodic arrangements, or (xvii) 3D periodic arrangements;however in all preferred embodiments the layer of coating material ismechanically-stable at the interface between the substrate material andthe coating, independent of whether the composition, structure,functionality or arrangement is chemically-altered prior to thefabrication of the electrochemical cell, during the formation step ofthe electrochemical cell, or throughout the useful life of theelectrochemical cell.

The coating of Embodiment 1, wherein the layer of coating materialfurther includes one or more of a metal selected from a group consistingof: alkali metals; transition metals; lanthanum; boron; silicon; carbon;tin; germanium; gallium; aluminum; titanium, and indium. The coating ofEmbodiment 1, wherein the layer of coating material has a thickness ofless than or equal to about 2,500 nm, or between about 2 nm and about2,000 nm, or about 10 nm, or a thickness of about 5 nm to 15 nm. Thecoating of Embodiment 1, wherein the layer of coating material isuniform or non-uniform on the surface, conforms to the surface, and/oris preferentially continuous or discontinuous, either randomly orperiodically, on the surface of any substrate.

In some embodiments, the thickness, uniformity, continuity and/orconformality may be measured using an electron microscope, and maypreferentially have a deviation from a nominal value of at most 40%,most often 20%, and sometimes 10% or lower, across any or all coatingmaterials. An additional unexpected observation of Embodiment 1 was thatthe features and benefits of some or all layers comprising one or moreof (i)-(xvi) above coated on the cathode, anode or solid electrolytematerials could be achieved even with non-uniform, discontinuous and/ornon-conformal layers, in which a minimum of 40% variation, most often80% variation, oftentimes even up to 100% variation, yet at maximum upto 400% variation. With respect to frequency, standard deviations,reproducibility, and/or random error, the variation observationsdescribed herein generally hold true at least 95% of the time.

The coating of Embodiment 1, wherein the layer of coating materialfurther includes one or more of: complexes of aluminum, lithium,phosphorous, boron, titanium or tin cations with organic species withhydroxyl, amine, silyl or thiol functionality, especially being derivedfrom glycol, glycerol, glucose, sucrose, ethanolamine, or diamines. Thecoating of Embodiment 1, wherein the layer of coating material furtherincludes alumina, titania, nitrogen-niobium-titanium oxide, or LiPON,and is coated on a lithium-nickel-manganese-cobalt-oxide (NMC) surface,a lithium-nickel-cobalt-aluminum-oxide (NCA) surface, or an NMC or NCAsurface that is enriched or deficient in lithium, manganese, cobalt,aluminum, nickel or oxygen, where the term ‘rich’ or ‘deficient’ cangenerally imply at a 0.1% to 50% deviation from stoichiometry, sometimes0.5% to 45%, oftentimes 5% to 40%, and most often 10% to 15%, 20% to25%, or 35% to 40%.

The coating of Embodiment 1, wherein the layer of coating material iscoated on a material comprising one or more of a graphite, lithiumtitanate, silicon, silicon alloy, lithium, tin, molybdenum containingsurface, or may further be deposited on a carbon-based conductiveadditive, a polymeric binder material, a current collector that is usedalongside any coated cathode active material, anode active material, orsolid state electrolyte material of the electrochemical cell.

When a battery is made using materials from Embodiment 1, the layer ofmaterial deposited on the surface of the anode active material or thecathode active material can provide the battery with longer lifetime,higher capacity with number of charge-discharge cycles, reduceddegradation of the constituent components, increase a discharge ratecapacity, increase safety, increase the temperature at which thermalrunaway occurs, and allow for safer higher voltage operation duringnatural or unnatural phenomena or occurrences.

A battery comprising one or more deposited material layers of Embodiment1 can demonstrate a Peukert Coefficient that is either 0.1 lower than abattery devoid of said deposited material layer or layers, or 1.1 orlower, or both. The battery of Embodiment 1, wherein the layer ofmaterial deposited on the surface of the anode active material or thecathode active material allows the battery to pass a nail penetrationtest at a voltage of 4.05 V or higher, sometimes 4.10 V or higher, andsometimes 4.20 V or higher. A battery of Embodiment 1 can alsodemonstrate higher thermal runaway, with a thermal runaway temperatureat least 25° C. higher, most often 35° C. higher and often 50° C. higheror more, relative to a battery that is devoid of one or more depositedlayer materials on the surfaces of the constituent electroactivematerials.

In some embodiments, the layer of material is coated on at least one ofthe cathode active material or the anode active material prior to mixingthe coated at least one of the cathode or anode active material to formactive material slurries for electrode casting for cells that are atleast 2 Ah in size, most often at least 15 Ah, oftentimes at least 30 Ahand sometimes 40 Ah or larger, and wherein the layer of materialmitigates gelation phenomena and occurrences during a batterymanufacturing process. In this embodiment, the active material slurryviscosity is always less than 10 Pas over a shear rate range of 2 s⁻¹ to10 s⁻¹ shear rates. The slurry viscosity using uncoated materials may behigher than 10 Pas at a shear rate of 5 s⁻¹, or higher than 5 Pa·s at ashear rate of 20 s⁻¹ or higher, whereas the slurry viscosity usingactive materials with deposited layer coating materials shows at least a10% reduction, most often a 20% reduction, often a 30% reduction andsometimes a 40% reduction in viscosity at a given shear rate. Inaddition, the hysteresis behavior, as measured by the difference betweenthe measured viscosity at increasing versus decreasing shear rates is atleast 10% lower, most often 20% lower, oftentimes 30% lower, andsometimes 40% lower at a given shear rate.

In certain embodiments, the property improvements to a battery can besimilarly enhanced using two or more distinct coating layer materialswith a particular composition, structure, functionality, thickness orordering, however when combined or cladded as a multi-layer,multi-functional coating, wherein layers in the multi-layer coating arearranged in a predetermined combination and a predetermined order toprovide similar or different properties or functions compared to oneanother, such that the total coating has more or greater properties thana coating formed by any single distinct coating layer.

In certain embodiments, the layer of material forms strong bonds betweencoating atoms and surface oxygen. In certain embodiments, the layer ofmaterial is coated on at least one of the anode or cathode activematerials for use of the active materials with a BET of greater than 1.5m²/g and particle size of the active materials smaller than 5 μm. Insome embodiments, the layer of material is coated on at least one of theanode or cathode active materials to form electrodes that do not containadditives besides the coated active materials, and/or utilizeelectrolytes that have fewer or no electrolyte additives.

In some embodiments, the layer of material is coated on at least one ofthe anode or cathode active materials for at least one of controlledsurface acidity, basicity, and pH, where the pH of the active materialsubstrate with said layer of coating material is at least 0.1 higher orlower than that of the active material substrate devoid of a layer ofcoating material. Control over pH and other aspects of surfaces andcompositions has practical ramifications in battery manufacturing, aselectrodes cast from active materials comprising a layer of coatingmaterial may become more advantageous for aqueous, UV, microwave, ore-beam slurry preparation and electrode casting, curing and/or drying.

The materials that include a layer of coating material may reduce therequired energy input or time to process, cure, dry or otherwise carryout a step in a manufacturing process by at least 5%, most often by atleast 10%, often by at least 15% and sometimes by at least 20%. Inaddition, certain embodiments wherein the layer of material is coated onat least one of the anode or cathode active materials provide forelectrode and battery manufacturing without environment humiditycontrol.

In some embodiments wherein the layer of material is coated on at leastone of the anode or cathode active materials for battery production witha simplified or eliminated formation step. In some embodiments, theformation time or energy consumption or both are reduced by at least 10%relative to battery production without said layer of material. In otherembodiments, the layer of material is coated on at least one of theanode or cathode active materials for increased wettability ofelectrodes with electrolyte, changing the contact angle by at least 2°,most often by 5°, and sometimes by 10° or more.

In some embodiments, the layer of material forms strong bonds betweencoating atoms and surface oxygen. As embodied herein, the layer ofmaterial may be coated on at least one of the anode or cathode activematerials for use of the active materials with a BET of greater than 1.5m²/g and particle size of the active materials smaller than 5 μm, andmay be used to further reduce gas generation by at least 1%, most oftenby 5%, sometimes by 10% and even by 25% or more.

Further, the elements or components of the various embodiments disclosedherein may be used together with other elements or components of otherembodiments.

It is intended that the specification and examples be considered asexemplary only, with a true scope and spirit of the invention beingindicated by the following claims.

We claim:
 1. An ionically-conductive coating for a cathode activematerial, an anode active material, or a solid state electrolyte for usein a battery, comprising: a layer of coating material disposed on asurface of the cathode active material, the anode active material, orthe solid state electrolyte; the layer of coating material comprisingone or more of a: (i) metal oxide; (ii) metal halide; (iii) metaloxyflouride; (iv) metal phosphate; (v) metal sulfate; (vi) non-metaloxide; (vii) olivine; (viii) NaSICON structure; (ix) perovskitestructure; (x) spinel structure; (xi) polymetallic ionic structure;(xii) metal organic structure or complex; (xiii) polymetallic organicstructure or complex; (xiv) structure with periodic properties; (xv)functional groups that are randomly distributed; (xvi) functional groupsthat are periodically distributed; (xvii) functional groups that arecheckered microstructure; (xviii) 2D periodic arrangement; and (xix) 3Dperiodic arrangement; and the layer of coating material beingmechanically-stable.
 2. The coating of claim 1, wherein the layer ofcoating material further comprises one or more of a metal selected froma group consisting of: alkali metals; transition metals; lanthanum;boron; silicon; carbon; tin; germanium; gallium; aluminum; titanium; andindium.
 3. The coating of claim 1, wherein the layer of coating materialhas a thickness of less than or equal to about 2,500 nm; or a thicknessbetween about 2 nm and about 2,000 nm; or a thickness of about 10 nm; ora thickness of about 5 nm to 15 nm.
 4. The coating of claim 1, whereinthe layer of coating material is uniform on the surface; or the layer ofcoating material conforms to the surface; or the layer of coatingmaterial is continuous on the surface.
 5. The coating of claim 1,wherein the layer of coating material is non-uniform on the surface. 6.The coating of claim 1, wherein the layer of coating material furthercomprises one or more of: complexes of aluminum cations and glycerol; orcomplexes of aluminum cations and glucose.
 7. The coating of claim 1,wherein the layer of coating material further comprises alumina, and iscoated on a lithium-nickel-manganese-cobalt-oxide surface; or the layerof coating material further comprises alumina, and is coated on alithium-nickel-cobalt-aluminum-oxide surface; or the layer of coatingmaterial further comprises alumina, and is coated on a lithiumrich-nickel-manganese-cobalt-oxide surface; or the layer of coatingmaterial further comprises alumina, and is coated on a graphite surface;or the layer of coating material further comprises alumina, and iscoated on a lithium titanate surface; or the layer of coating materialfurther comprises titania, and is coated on alithium-nickel-cobalt-aluminum-oxide surface; or the layer of coatingmaterial further comprises titania, and is coated on a lithiumrich-nickel-manganese-cobalt-oxide surface; or the layer of coatingmaterial further comprises titania, and is coated on alithium-nickel-manganese-cobalt-oxide surface; or the layer of coatingmaterial further comprises titania, and is coated on a graphite surface;or the layer of coating material further comprises titania, and iscoated on a lithium titanate surface; or the layer of coating materialfurther comprises LiPON, and is coated on alithium-nickel-manganese-cobalt-oxide surface; or the layer of coatingmaterial further comprises LiPON, and is coated on alithium-nickel-cobalt-aluminum-oxide surface; or the layer of coatingmaterial further comprises LiPON, and is coated on a lithiumrich-nickel-manganese-cobalt-oxide surface; or the layer of coatingmaterial further comprises LiPON, and is coated on a graphite surface;or the layer of coating material further comprises LiPON, and is coatedon a lithium titanate surface; or the layer of coating material furthercomprises a nitrogen-niobium-titanium oxide, and is coated on a siliconsurface.
 8. A battery, comprising: an anode; a cathode; an electrolyteconfigured to provide ionic transfer between the anode and the cathode;and a layer of material deposited on a surface of an anode activematerial and/or a cathode active material; the layer of materialcomprising one or more of a: (i) metal oxide; (ii) metal halide; (iii)metal oxyflouride; (iv) metal phosphate; (v) metal sulfate; (vi)non-metal oxide; (vii) olivine; (viii) NaSICON structure; (ix)perovskite structure; (x) spinel structure; (xi) polymetallic ionicstructure; (xii) metal organic structure or complex; (xiii) polymetallicorganic structure or complex; (xiv) structure with periodic properties;(xv) functional groups that are randomly distributed; (xvi) functionalgroups that are periodically distributed; (xvii) functional groups thatare checkered microstructure; (xviii) 2D periodic arrangement; and (xix)3D periodic arrangement.
 9. The battery of claim 8, wherein the layer ofmaterial further comprises one or more of a metal selected from a groupconsisting of: alkali metals; transition metals; lanthanum; boron;silicon; carbon; tin; germanium; gallium; aluminum; titanium; andindium.
 10. The battery of claim 8, wherein the layer of material has ameasured nominal thickness of less than or equal to 2,500 nm; or between2 nm and 2,000 nm; or 0.1 nm to 15 nm; or is about 10 nm.
 11. Thebattery of claim 8, wherein the layer of material deposited on thecathode active material is 0.1 nm to 15 nm in measured nominalthickness, and the layer of material deposited on the anode activematerial is 2 nm to 2,000 nm in measured nominal thickness.
 12. Thebattery of claim 10, wherein a measured nominal thickness variation doesnot exceed 40% from a reference measured nominal thickness in at least95% of measured thicknesses.
 13. The battery of claim 8, wherein thelayer of material further comprises one or more cations of: lithium,aluminum, boron, titanium, phosphorous or tin, complexed with an organicmolecule comprising at least two functional groups selected from: ahydroxyl, an amine and/or a thiol group.
 14. The battery of claim 8,wherein the layer of material further comprises one or more of aluminumoxide, titanium dioxide, or lithium phosphorous oxynitride, and iscoated on one or more of a lithium-nickel-cobalt-aluminum-oxide,lithium-nickel-manganese-cobalt-oxide, lithium-manganese-oxide,lithium-cobalt-oxide, graphite, silicon, or lithium-titanium-oxidesurface.
 15. The battery of claim 8, wherein the layer of materialdeposited on the surface of the anode active material or the cathodeactive material increases a discharge rate capacity, and provides saidbattery with a Peukert Coefficient that is either 0.1 lower than abattery in which the layer of material was not deposited; or a PeukertCoefficient that is 1.1 or lower; or a Peukert Coefficient that is 0.1lower than a battery in which the layer of material was not depositedand that is 1.1 or lower.
 16. The battery of claim 8, wherein the layerof material deposited on the surface of the anode active material or thecathode active material allows the battery to pass a nail penetrationtest at a voltage of 4.05 V or higher.
 17. The battery of claim 8,wherein the layer of material is deposited on at least one of thecathode active material or the anode active material prior to mixing thecoated at least one of the cathode or anode active material to formactive material slurries for electrode casting for a battery of 2 Ah orgreater, and wherein the layer of material mitigates gelation phenomenaand occurrences during a battery manufacturing process, and wherein theactive material slurry viscosity is always less than 10 Pa·s over ashear rate range of 2 s⁻¹ to 10 s⁻¹ shear rates.
 18. The battery ofclaim 8, wherein the layer of material includes a multi-layer,multi-functional coating, wherein layers within the multi-layer coatingare arranged in a predetermined combination and a predetermined order toprovide similar or different properties or functions compared to oneanother, such that the total coating has more or greater properties thana coating formed by any single layer of equivalent thickness.
 19. Thebattery of claim 8, wherein a thermal runaway onset temperature is atleast 25° C. higher than a battery without said layer of material. 20.The battery of claim 8, wherein the layer of material is deposited on atleast one of the anode or cathode active materials for at least one ofcontrolled surface acidity, basicity, and pH and wherein the surface pHof the layer of material coated active material is changed by at least0.1 relative to the uncoated active material.
 21. The battery of claim8, wherein the layer of material is deposited on at least one of theanode or cathode active materials for aqueous, UV, microwave or e-beamslurry preparation and electrode casting, curing and/or drying.
 22. Thebattery of claim 8, wherein the layer of material is deposited on atleast one of the anode or cathode active materials for batteryproduction with simplified or eliminated formation step and wherein theformation time or energy consumption or both are reduced by at least 10%relative to battery production without said layer of material.
 23. Abattery, comprising: an anode; a cathode; an electrolyte configured toprovide ionic transfer between the anode and the cathode; a solid stateelectrolyte material positioned within at least one of the anode,cathode and electrolyte; and a layer or layers of material deposited ona surface of the anode active material, the cathode active material,and/or the solid state electrolyte material; the layer of materialcomprising one or more of a: (i) metal oxide; (ii) metal halide; (iii)metal oxyflouride; (iv) metal phosphate; (v) metal sulfate; (vi)non-metal oxide; (vii) olivine; (viii) NaSICON structure; (ix)perovskite structure; (x) spinel structure; (xi) polymetallic ionicstructure; (xii) metal organic structure or complex; (xiii) polymetallicorganic structure or complex; (xiv) structure with periodic properties;(xv) functional groups that are randomly distributed; (xvi) functionalgroups that are periodically distributed; (xvii) functional groups thatare checkered microstructure; (xviii) 2D periodic arrangement; and (xix)3D periodic arrangement.
 24. The battery of claim 23, wherein the solidstate electrolyte material comprises at least one of alithium-conducting sulfide-based, phosphide-based or phosphate-basedcompound, an ionically-conductive polymer, a lithium or sodiumsuper-ionic conductor, an ionically-conductive oxide or oxyfluoride,lithium phosphorous oxynitride, lithium aluminum titanium phosphate,lithium lanthanum titanate, lithium lanthanum zirconate, Li or Na betaalumina, a Garnet structure, LiSICON or NaSICON structures, or aperovskite structure.
 25. The battery of claim 23, wherein the layer ofmaterial further comprises one or more of a metal selected from a groupconsisting of: alkali metals; transition metals; lanthanum; boron;silicon; carbon; tin; germanium; gallium; aluminum; titanium; andindium.
 26. The battery of claim 23, wherein the layer of material havea measured nominal thickness of less than or equal to 2,500 nm; orbetween 2 nm and 2,000 nm; or 0.1 nm to 15 nm; or is about 10 nm. 27.The battery of claim 23, wherein a layer of material deposited on thesolid state electrolyte is 0.2 nm to 100 nm, and the battery includes atleast one of: a layer of material deposited on the anode active materialthat is 2 nm to 2,000 nm in measured nominal thickness, and a layer ofmaterial deposited on the cathode active material that is 0.1 nm to 15nm in measured nominal thickness.
 28. The battery of claim 23, whereinthe anode comprises lithium metal particles coated with a layer ofmaterial having a thickness of 100 nm or less.
 29. The battery of claim23, which has a first cycle discharge capacity that is at least 100%higher than a corresponding battery in which a layer or layers ofmaterial is not deposited on a surface and both said battery and saidcorresponding battery are otherwise fabricated under the sameconditions.
 30. The battery of claim 23, wherein the layer of materialon the solid state electrolyte material controls the growth of a nativeoxide at the solid state electrolyte material surface in ambient air tono more than about 5 nm in thickness, and/or maintains an oxygen contentof the solid electrolyte particle to no more that about 5% afterexposure to ambient air for 24 hours.
 31. The battery of claim 23,wherein the layer of material on the solid state electrolyte material isadapted to maintain an ionic conductivity of at least 10⁻⁶ S cm⁻¹ after1 hour of exposure to ambient air.
 32. A process for coating a cathodeactive material, an anode active material, or a solid state electrolytematerial of a battery, comprising: depositing a layer of material on asurface of the cathode active material, the anode active material, orthe solid state electrolyte material of the battery by one or more of:atomic layer deposition; chemical vapor deposition; vacuum deposition;electron beam deposition; laser deposition; plasma deposition; radiofrequency sputtering; sol-gel; microemulsion; successive ionic layerdeposition; aqueous deposition; mechanofusion; solid-state diffusion; ordoping; wherein the layer of material comprises one or more of a: (i)metal oxide; (ii) metal halide; (iii) metal oxyflouride; (iv) metalphosphate; (v) metal sulfate; (vi) non-metal oxide; (vii) olivine;(viii) NaSICON structure; (ix) perovskite structure; (x) spinelstructure; (xi) polymetallic ionic structure; (xii) metal organicstructure or complex; (xiii) polymetallic organic structure or complex;(xiv) structure with periodic properties; (xv) functional groups thatare randomly distributed; (xvi) functional groups that are periodicallydistributed; (xvii) functional groups that are checkered microstructure;(xviii) 2D periodic arrangement; and (xix) 3D periodic arrangement. 33.The process of claim 32, wherein the solid state electrolyte material isfurther produced using a process that comprises: depositing a first,solid electrolyte coating having a thickness of 60 μm or less on aporous, flexible scaffold by one or more of: atomic layer deposition;chemical vapor deposition; vacuum deposition; electron beam deposition;laser deposition; plasma deposition; radio frequency sputtering;sol-gel; microemulsion; successive ionic layer deposition or aqueousdeposition, wherein the solid state electrolyte material comprises atleast one of a lithium-conducting sulfide-based, phosphide-based orphosphate-based compound, an ionically-conductive polymer, a lithium orsodium super-ionic conductor, an ionically-conductive oxide oroxyfluoride, lithium phosphorous oxynitride, lithium aluminum titaniumphosphate, lithium lanthanum titanate, lithium lanthanum zirconate, Lior Na beta alumina, a Garnet structure, LiSICON or NaSICON structures,or a perovskite structure.
 34. A battery, comprising: an anode; acathode; a flexible solid state electrolyte configured to provide ionictransfer between the anode and the cathode; and a layer or layers ofmaterial deposited on a surface of the anode active material, thecathode active material, and/or the solid state electrolyte material;each layer of material comprising one or more of a: (i) metal oxide;(ii) metal halide; (iii) metal oxyflouride; (iv) metal phosphate; (v)metal sulfate; (vi) non-metal oxide; (vii) olivine; (viii) NaSICONstructure; (ix) perovskite structure; (x) spinel structure; (xi)polymetallic ionic structure; (xii) metal organic structure or complex;(xiii) polymetallic organic structure or complex; (xiv) structure withperiodic properties; (xv) functional groups that are randomlydistributed; (xvi) functional groups that are periodically distributed;(xvii) functional groups that are checkered microstructure; (xviii) 2Dperiodic arrangement; (xix) 3D periodic arrangement; and wherein thesolid state electrolyte material is deposited onto a porous, flexiblescaffold, and comprises at least one of: a lithium-conductingsulfide-based, phosphide-based or phosphate-based compound, anionically-conductive polymer, a lithium or sodium super-ionic conductor,an ionically-conductive oxide or oxyfluoride, lithium phosphorousoxynitride, lithium aluminum titanium phosphate, lithium lanthanumtitanate, lithium lanthanum zirconate, Li or Na beta alumina, a Garnetstructure, LiSICON or NaSICON structures, or a perovskite structure.